Two decades in, Tom Brady's stranglehold on the rest of the NFL appears strong as ever. His reign, unquestioned. His swagger, intact.

You see him strut through his team's locker room, and the smirk assures he's the same diabolical competitor who'll reach into your chest, extract your heart and bid you farewell.

You see him knife the ball through a proud Vikings defense with ease, eviscerate the Dolphins secondary for 358 yards and three touchdowns last week, and you know that even at 41 years of age, this is still the same player whose dominance is unparalleled. Five rings. Three MVPs. The most wins in NFL history.

Yet, this season, there have been hints of erosion. Signs that Tom Brady may not be Tom Brady anymore. At the Week 11 mark, before this recent surge, his 59.6 passer rating against the blitz (per ESPN) ranked dead last in the NFL—he used to feast on blitzes. His current 65.6 completion percentage, 3,700 passing yards, 23 touchdowns and 98.2 overall rating are all middle of the pack.

The Patriots are rolling along to another division title, but Brady has been outperformed by a new generation of passers.

The greats all fall, and it's never pretty.

Joe Montana called it quits after 187 total starts, Dan Marino after 258, Peyton Manning after 292, Brett Favre after 322. This coming Sunday will mark Brady's 302nd. Maybe Brady can will himself into a stratosphere never reached before. He's been shutting up critics his entire life. But with another postseason approaching, with battles against Patrick Mahomes and Philip Rivers and Deshaun Watson looming, that question—Is Tom still Tom?—will be put under the microscope like never before.

In search of an answer, Bleacher Report has spent the past week conducting a virtual roundtable with some of the best football minds.

Everyone is in agreement that, this January, the truth will be told.

Here's our panel:

Warren Moon: Hall of Famer, nine-time Pro Bowler, 10th on the all-time passing list.

Drew Bledsoe: Longtime Patriot, four-time Pro Bowler, former Brady teammate, 15th on the all-time passing list.

Joe Theismann: Super Bowl XVII champion, two-time Pro Bowler, 1983 NFL MVP.

Matt Hasselbeck: Led Seattle to an NFC title, three-time Pro Bowler, 26th on the all-time passing list, current ESPN analyst.

Bruce Arians: Former Colts and Cardinals head coach, known as a "QB Whisperer" (coached Peyton Manning, Ben Roethlisberger, Andrew Luck and Carson Palmer).

Trent Green: Two-time Pro Bowler, 56th on the all-time passing list, current CBS analyst.

Darren Woodson: Hall of Fame semifinalist safety, three-time Super Bowl champ, five-time Pro Bowler, current ESPN analyst.

Tom House: QB guru who has served as one of Tom Brady's personal quarterback coaches the last seven years.

Tom vs. Time

To Warren Moon, erosion is sad but inevitable. At some point, as a quarterback, your body cannot do what your mind tells it.

He tried all the same types of tricks as Brady has. He became a vegetarian. He revved up his training. In Houston's run-and-shoot offense—receivers replacing blockers to the extreme—Moon knew he needed to stay at his absolute physical peak. He had his own version of Brady health guru Alex Guerrero in Oilers trainer Steve Watterson and continued to follow Watterson’s workouts after he left Houston. Like Brady now, Moon zeroed in on specific goals each offseason. His legs. His flexibility. His core. And at 41, Moon was essentially Brady before Brady. With the Seahawks, in 14 games, he threw for 3,678 yards, 25 touchdowns and was named MVP of the Pro Bowl when that game actually meant something.

The next year, Moon cracked his ribs, tried playing through the injury, struggled and was benched. He moved to Kansas City the following year and was finished.

If he would've just let those ribs heal, Moon half-jokes, maybe he's still playing today.

One way or another, he knows Father Time wins.

Moon: The numbers are starting to show that there's a deterioration coming. Especially when you talk about the blitzing because that's something he used to really excel at. You do start to lose some of your reflexes and responses. I started to figure that out later on in my career, too. Even though your mind knows where you should be going, sometimes your body just doesn't react as fast. You're starting to see some of that with him.

Arians: There's a little decline but not much. When you look at the great quarterbacks, you'd never call any of them great athletes. When you think of Johnny Unitas and Marino and Manning and Brady and Joe Namath, they played in the pocket.

Woodson: Are we seeing Tom Brady drive the ball down the field like he's done in the past? Not as much. But I don't think there's a falloff. Mentally, he's so smart in understanding exactly what's in front of him. Knowing exactly how to dissect defenses. And I think the Patriots do a great job of protecting him in the pocket. So I don't see the decline.

Theismann: I don't see the arm getting weaker. I don't see the release getting weaker. I don't see any movement in the pocket getting any slower. I see a decisiveness. I see a fire.

Green: For me, the thing I could tell as you get older is the velocity changes. So with velocity, you also lose distance. But, in reality, the majority of your throws aren't going over 50 yards. I could still throw 50 yards now. I'm just saying it's a different velocity to get to 50 yards. ... But he's still making all the throws necessary.

Moon: Most people think with a quarterback, it's your arm. Your arm is important, but if you don't have your legs working with the rest of your body—being able to have those quick-twitch movements to move in the pocket to slide and buy yourself a bit more time—those are the things you start to see that don't happen as fast. That's where Tom used to excel. Even though he's not a great athlete, a scrambler or anything like that, he could really slide and move around the pocket as well as any quarterback and manipulate the pocket. Those things are starting to slow down a little bit more for him as he gets a little bit older.

Theismann: With Tom, there's not an issue of movement. He makes his living with his arm and his head. His eyes are 20/20 as they've ever been.

Moon: I don't think you fall off a cliff, but it is gradual, and once that gradual [decline] starts, there's no turning back from it. It's not like you're going to recapture what you had before. I don't think he'll be able to go back and have another offseason where he can get back to the form he was two years ago. It's going to continue to keep sliding, and you just have to continue adjusting your game, and hopefully your offense and your offensive coaches will adjust and not have to rely on you as much to carry the football team as you have in the past.

Woodson: My question is, when you watch the quarterbacks who start to lose it, it's when they cannot drive the ball down the field. Especially when they're moving outside the pocket or trying to escape. Those are the question marks you start to have with quarterbacks. But the Patriots don't put him in those situations. They do a great job of protecting him. Let's put Brady or an aging quarterback on a team like the Cleveland Browns who can't protect. Then, we'll see the warts.

Green: I think we've all been spoiled because he's been so good for so long. And when I say "so good," I mean so much better than so many other people over the course of history. The fact is he's completing 66 percent of his passes, he's well on his way to having over 4,000 yards again. He's 2-to-1 in touchdowns-to-interceptions again. I think his quarterback rating is like a 97, 96.5. Those are great, great numbers. But when you compare it to what he's done his entire career, the bulk of his career, you're like, "Oh no! What's happening?"

Moon: Age is something none of us can avoid. Things are going to start to slow down. How fast? We really don't know. You can start to see some decline in Tom.

Internal forces

It was Super Bowl 50 and Tom Brady, forever the headliner on the game's marquee, was not in San Francisco to play football. No, he was there for endorsements and appearances like so many others. And at one such event, Joe Theismann asked Brady how he was doing.

Theismann expected Brady to say "Things are good!" or "Family's great!" Instead, Brady fumed with a searing glare.

"Terrible," Brady said.

"What do you mean, terrible?" asked Theismann, concerned.

"I hate being here. I belong out there on that football field."

To everyone, that's quintessential Tom Brady. A ruthless assassin who could excel deep into his 40s because nobody's wired like him. It's a borderline "sickness," friends say. He has never forgotten he was the 199th pick in the draft. He's obsessed with finding that "1 percent," that miniscule, impossible-to-see way to improve. Maybe then-teammate Kenny Britt put it best during Super Bowl week a year ago: "He's an alien! I don't even think he's from this universe to tell you the truth."

Stephon Gilmore calls it an inner "dog" that only the Bradys, Jordans, Kobes possess.

But how long can this maniacal drive—ring after ring—fuel Brady?

He should be inching closer to "E."

Hasselbeck: Every time we got ready to play him, our defensive coaches would say, "Hey, he's going to do this!" and "He's going to do that!" I really felt like our defensive coaches had a really solid handle on what Tom Brady was going to do. And every single time, he would do it anyway. We all knew the quarterback sneak was coming, and yet your 6'5", 220-pound frame, which is skinny, still just did an amazing job rushing for two yards. We know you're going to substitute and quick-count us here and catch us with 12 men on the field—we know it, we talked about it all week—and yet somehow you still got us.

Arians: The AFC Championship Game when I was in Pittsburgh. He was on fire that night. And any time he's playing a hotshot young [QB]—Andrew Luck a couple times, Mahomes—when he's playing the young ones he really wants to show out. There's no doubt. His competitive spirit is amazing.

Moon: That drive that he has right now is the same drive that got him to where he is. If he didn't have that drive when he came into the league, we never see Tom Brady. It's hard to give that up when that's a part of you.

Theismann: We all talk about Peyton and his preparation and the way he controlled a game. Tom does the same thing. When it comes to preparation, Tom is meticulous. Film study. Understanding the offense. Knows exactly what he wants to do and where he wants to do it. When you watch him on the football field, he is in total and complete control of the game.

Hasselbeck: Defensive coordinators, he's burned them so many times that they get psyched out. It becomes, "He burned us on the blitz that one time. We can't blitz him." And they stop blitzing him. Defensive players aren't just playing football. They're up there saying, "Man, I'm playing against The Tom Brady. The GOAT." And they don't play their own game. That's a real thing. Brett Favre had that a little bit. Reggie White had it a little bit. Randy Moss had it. Tom Brady has it. There's guys where the opponent gets psyched out before the competition even begins.

Arians: There's not a blitz you can show him he hasn't seen. If you show it to him once, he's got it. You're not going to get him with it twice.

House: His expectation level is pretty intense.

Moon: Once you can't do the things you used to do or the things the team asks you to do, maybe it's time to move on. I'm sure he's thought a lot about it.

Bledsoe: He's in a lot of ways still the same guy I met on the practice squad backing us up. He still has that same passion and enjoyment for the game. The thing that keeps him going is really the same thing he had when he got there. The thing that's most impressive is he's been able to maintain that enjoyment of the game and that enjoyment of preparing to play.

Moon: I think it has more to do with his desire than his physical abilities. What more can this guy do? He has five Super Bowl rings. He's been an MVP multiple times. He has a lot of records and he's closing in on some of the other ones. That would be my thing: What's going to keep motivating me and driving me to keep going out there at this age when you've got all the money in the world, you've got a beautiful family, you've got a wife who makes more money than you do, and he has tons of endorsements waiting for him when he wants to stop playing. What makes him keep going? I'm not sure. But let him play as long as he wants to.

Bledsoe: He's not playing because he needs to prove anything. He's playing because he wants to play. See, that's where the media in general gets lost in all this stuff. Oh, a guy has to play for his legacy or A guy has to play to prove something. Ultimately, it's a game, and you get to play it for a living. You do it as long as you can. ... There's nothing more that he enjoys in the world than playing and preparing to play football. If he was worried about legacy, he could have retired a long time ago.

House: He loves the game. His passion for football is like other elite athletes that play into their late 30s and early 40s, like Nolan Ryan coming to the ballpark. You just love the game. It's part of their fabric.

External forces

All that said, maybe what once and for all nudges Tom Brady into retirement is completely out of his control. Often, with the greats, it's one final hit. Steve Young, Troy Aikman, Jim Kelly, Brett Favre, Theismann, so many others suffered this fate. Often, it's deterioration. Peyton Manning walked away victorious after that Super Bowl 50 but was a skeleton of himself by then. Same for Dan Marino, who lost 62-7 in his final game. And Unitas, way back, as a 40-year-old relic in San Diego.

Brady's fighting back.

A completely new NFL helps him avoid that kill shot. As for the latter, his hope is that all the innovative work with House and Guerrero helps him delay...and delay...and delay his own 62-7 drubbing. House believes. He first tested his methods on MLB ace Nolan Ryan, and Ryan threw heat until he was 46. No, he won't reveal specifically what he does with Brady—as if quadruple padlocking those secrets in a faraway treasure chest—but as House explains, they match up nerves, muscle, connective tissue with forced plates and wireless EMG to track Brady's body movements.

And when he then watches a three-dimensional view of this all, down to a thousand frames per second, House insists the quarterback's functional strength and arm speed have not diminished. At all.

Of course, there are other factors, too. There's Bill Belichick and all the reported tension between the two that could nuke the dynasty entirely. And there's family. There are his three kids and a wife, Gisele Bundchen, who's on record saying she's worried about his unreported concussions.

Brady loves football, but could something else force him to walk away?

House: The aging process is obviously unforgiving. You hear announcers say that old age is just something that happens, and it's going to win in the long haul. But research says there's no reason you can't do at 45 what you did at 25 if your process will support it. What I've seen, and what we're researching, is that strength usually isn't the problem. They can maintain strength into their 50s. But flexibility and speed—the nervous system—they need to be addressed a little bit differently.

Bledsoe: Playing quarterback is not physically taxing. It's really not. Especially now, as a pocket passer. Tom, he doesn't get hit a lot. It's not like he's doing what LeBron James is doing. The physical toll that LeBron puts on the floor every night is really amazing. But being able to go out and throw the ball, to drop back a few steps. Tom was never going to make plays running around.

Woodson: (In Dallas), Troy [Aikman] lost his weapons. Michael Irvin was aging. Emmitt Smith started to age as well. And we couldn't protect him. He started taking the big shots. He couldn't avoid sacks. He couldn't get the ball out of his hands quick enough. And then you started to see the body fall apart. That's what's been spectacular about Brady. He's done a great job of taking care of his body. Troy started to fall apart physically because of back problems, and concussions compounded that.

Theismann: I wouldn't even want to bring it into the universe. I want to see him ride off into the sunset like John Elway.

Bledsoe: He's never really been hit very much. So the physical toll on his body, that's really not what it's about. For him, it's different outside any other position than kicker or punter in the league. You're really not taking the physical punishment.

Hasselbeck: He's not normal. So he's not living a normal life. He's not doing what most people are doing. He's made sacrifices in his diet. Whatever he's doing is working. If you look at a picture of him versus a picture of him his rookie year, he looks younger now than he did when he started. And that's just his looks. He's probably quicker. He's probably more agile. He's always looking for the next thing, always looking for the next edge in ways to train better, recover better, eat better, live better.

House: I actually think he's a better quarterback now than 10 years ago. Because in his head, he has 10 years of experience and his body has maintained. He's as good or better physically as he was 10 years ago.

House: This generation of quarterback has hit the perfect crease. The Germans call it zeitgeist. The Marinos and the Montanas probably had the same drive. They probably had similar tools. But what they didn't have was the current science, the current research that allows them to do something long term biomechanically better, long term physically better, long term mentally and emotionally, and long term with nutrition and sleep for recovery. It's the perfect storm, and the generation that's coming behind them is going to be even better because science doesn't stand still.

Woodson: When the Patriots played the Green Bay Packers, people were saying that if Aaron Rodgers played for Bill Belichick, he'd have five, six, seven Super Bowl rings. There's something to be said about the mental toughness. Physically, yeah, there's better quarterbacks in this league than Tom Brady. Physically, that can make the throws, throw off-platform, throw the ball 100 miles and are probably more accurate. But the mental toughness that he plays with—that's where he separates himself from everyone. The ability to go out week in and week out, under pressure, play at that level, play in that many AFC Championship Games, play a full schedule of 19, 20 games and then come back the next year and play another 20 games—under the toughest, most grind-it-out coach in the history of the game—in Bill Belichick, no one can do that. That speaks to who he is. No way is Aaron Rodgers is going to deal with Bill Belichick for that amount of time without his ego popping up. Brady's special in the fact that it's not about him, man. That's why I feel like he'd be the ultimate teammate. Tedy Bruschi would tell you in a heartbeat, he's a great teammate because there's not a selfish bone in his body. It's about winning—at all costs—and that means everybody's on board.

Hasselbeck: You're Tom Brady. You're the best of the best. And when people ask him a question, he says, "We'll have to see what coach decides he wants to do about that." He realizes that he's the quarterback and not the head coach. I read last year about Kevin Durant, how he's the most talented player on the team but he practices like the guy most likely to be cut next. I really always appreciated that about Tom Brady. He's coachable. Sometimes, when you know you know more or see it better than the coach, the best thing for you to do as a teammate and a player is to still be coachable. That's one of the reasons he's gotten better each and every year.

Theismann: Coaches control the football team. Quarterbacks, to a large degree, control the game. You have two very strong personalities. You have people who share a common interest—winning a football game—it's just that sometimes you don't see eye to eye. But you never let that get in the way of what the ultimate goal is. Didn't we hear of all the discord in New England in the offseason? Whatever happened to all of that banter? It's gone.

Arians: [Brady and Belichick] both love winning. That's what they do.

Hasselbeck: I think the hardest thing about playing into your 40s is that you're a father. When I was younger in my career, I would come home and I'd lay down to take a nap with the baby who's taking a nap at that time. When I was 40, I'd come home and my kids need help on their homework. I've got a 13-year-old. My kids want to shoot hoops or play catch or talk about the game—it's a different dynamic when you're all of a sudden raising a family. It's the hidden piece that I never considered and no one talks about or thinks about. But to be an all-pro Dad and an All-Pro quarterback, it's hard enough to do one of them. It's even harder to do both.

Moon: Once you can't do the things you used to do or the things the team asks you to do, maybe it's time to move on. I'm sure he's thought a lot about it. I know his wife has made comments the last couple of years and she's worried about some of the concussions he said he had but have never been reported. So there are probably more ongoing discussions within the family than there are publicly.

Hasselbeck: It's a seven-day-a-week job once the season starts, and you don't get that time back. I don't care how much money you have or how good you are. You can't get the time back.

Living in the now

Those close to Tom Brady insist he's no fan of any "GOAT" debate because such a conversation insinuates that his career is finished when, in his mind, he's far from finished. He's not worried about his legacy because he's still writing his legacy.

This season hasn't been the same from Brady as say, 2007 or even 2017. New England is clearly trying to establish the run more as if bringing this reign full circle. Through the air, checkdowns to James White rule the day now. Listen closely, though, and even those checkdowns are fueled by Brady's brilliance. He tells White what route to run, you know, mid-route.

The Patriots will need the brilliance to continue. With Mahomes, Rivers and Watson all playing lights out, they need the greatest ever to play like the greatest ever.

A moment of truth awaits.

Hasselbeck: It's almost like the year hasn't started for Tom. ... There were games Rob Gronkowski could have played in and they said, "Nah, just rest up." It's sort of their way. It reminds me of the NBA playoffs. The Warriors don't really care. They're like, "We'll deal with the playoffs when the playoffs come. We're not concerned." Steve Kerr's like, "Yeah, you guys call the plays. I'm good." They just feel like a team that waddles around until it's after Thanksgiving, and that's when it gets real serious.

Theismann: It's almost like a light switch was flipped after the bye. They got some people back. They got some people healthy. It's like a rejuvenated football team.

Woodson: The only way we'll be able to tell [if Brady is still Brady] is if they're on the road, in January, and let's say they're in Kansas City and they get into another firefight and they put it on Brady's shoulders to win the football game. That's when we'll be able to tell if this is the same Tom Brady. ... You're going to have to be in a firefight in the AFC. Because you have top-of-the-line quarterbacks in Mahomes, Rivers, Ben Roethlisberger who are going to put up some points against that Patriots defense. So we're going to find out a lot about Tom Brady. I want to see the Old Brady come out and have to hang 30 or 40 points on someone.

Moon: He's dropped down some this year. I still think he's maybe in the top seven. There are some guys ahead of him the way they're playing.

Bledsoe: He's better now than he was five years ago.

Green: The all-time list, I have him at the top. I had Montana at the top for a long time. And overall, I have Tom at the top now. As far as where he is this year, I would say he's definitely top 10. Maybe even top five. Obviously Mahomes is having an incredible year. Jared Goff is having an incredible year. Russell Wilson is sneakily having a really good year when you look at what he's done.

House: This is my seventh year with him and I haven't seen any skill diminishing anywhere. He's the same guy with more experience, more knowledge, and basically he is kind of like a coach unto himself. He has all that experience, all that knowledge and the ability to go out and recall it in competition, and he's kept his physical tools also.

Theismann: He is the greatest who ever played the game. Joe Montana is definitely in that conversation. But the thing that I look at with Tom is Joe had a fairly consistent group around him when they won those championships. That football team pretty much stayed intact for quite a while. Tom has had so many different receivers, so many different line combinations, so many different running backs.

Moon: If they would've won that Super Bowl this past year, this is just my opinion, he would've retired. I think he would've gone off into the sunset like a John Elway.

Hasselbeck: I think next year will be his last year. That's my guess. I think it'll have more to do with time with family than it has to do with desire to play.

Arians: I don't know if he'd give it up if he won another Super Bowl or not. He'd probably go for another one.

Tyler Dunne covers the NFL for Bleacher Report. Follow him on Twitter: @TyDunne.