On the wrong side of 30 and down maybe a quarter-step from his prime, J.J. Watt is no longer the player he once was. Wear, tear and multiple significant injuries will do that.

But before suffering a torn pectoral Sunday against the Oakland Raiders, the three-time Defensive Player of the Year was holding a mediocre defense together. 

Watt had just four sacks before his 2019 campaign came to an abrupt conclusion, but he leads the NFL with 20 quarterback hits, and no other player has more than 15. He also recovered a pair of fumbles and recorded three passes defensed in half a season of work. 

Among the 95 players with 160-plus defensive pass-rushing snaps this season, Watt ranked fourth in pass-rush grade and second in pass-rush win rate at Pro Football Focus.

He wasn't likely going to match his 2018 sack total of 16 or force seven fumbles for the second season in a row, but his loss could still crush the Texans. 

Watt's presence alone has helped D.J. Reader come along as an interior rusher, and it's a big reason teammate Whitney Mercilus has a team-high 5.5 sacks and a tied-for-league-best four forced fumbles. Watt is still the first player opposing offensive coordinators have to account for, and now he's no longer a factor. 

But it'll hurt beyond that because the Texans essentially put all of their eggs on defense in Watt's basket when they let Tyrann Mathieu get away in free agency and then traded Jadeveon Clowney. Those three were arguably the top three defenders on the team last season, and now the Texans are without all of them as they prepare for a home stretch in which they'll have to deal with the Baltimore Ravens, Indianapolis Colts and New England Patriots in consecutive weeks. 

At least this happened before the trade deadline, right? Wrong, because the Texans have been hemorrhaging draft capital all year. They dealt two first-round picks (one in 2020, another in 2021) and a 2021 second-round pick to the Miami Dolphins for offensive tackle Laremy Tunsil and two Day 3 selections, and they traded the third-round pick they got for Clowney to the Oakland Raiders for cornerback Gareon Conley. Oh, and they'll owe their own third-round selection to the Cleveland Browns as soon as running back Duke Johnson is active for his 10th game of the season (he's suited up for all eight, and it's at least a fourth-rounder regardless). 

Under those circumstances, potentially acquirable defensive difference-makers like Von Miller, Ryan Kerrigan, Yannick Ngakoue, Geno Atkins and Vic Beasley will likely be out of Houston's price range. A trade for a player like that would likely leave Houston with no picks in the first three rounds of the 2020 draft, and it already has none in the first two rounds of the 2021 draft. 

The Texans can't go all-in now, because they already did. And now they might be forced to fold on the river. 

Now, a defense that has allowed 27.5 points per game and generated just four takeaways and four sacks since Week 5 could be at risk of falling off a cliff. 

We got a potential peek at that fall on Sunday when the Raiders put together two long scoring drives in the second half after Watt left the game. The Texans ultimately surrendered a silly 7.1 yards per play while registering zero sacks and zero takeaways. 

It was one of Oakland's best offensive performances since the return of Jon Gruden.

It would be one thing if this were a short-term injury, or their only significant injury, but defensive backs Johnathan Joseph (shoulder, hamstring), Bradley Roby (hamstring) and Tashaun Gipson Sr. (back) were all out against the Raiders, they lost corner Lonnie Johnson Jr. to a concussion, starters Tytus Howard and Will Fuller V remain out on the offensive side of the ball, and they lost left tackle Laremy Tunsil to a shoulder injury on Sunday. 

And while anything's possible with MVP candidate Deshaun Watson running the offense, that lack of support could become too much for Watson and Co. to overcome. They're already half a game and a tiebreaker back of the division-leading Colts, they'll likely have to fight to get a W against Jacksonville before their bye, and then they'll be Watt-less against Lamar Jackson, Frank Reich and Bill Belichick.

They could easily drop all four of those games, while a 2-2 stretch would probably be considered successful under these circumstances. Even with a forgiving December schedule after the New England game, it's beginning to look like it once again isn't Houston's year. 

The AFC South is no longer the cakewalk it used to be. Nobody in that division has a losing record, and Indianapolis, Jacksonville and the Tennessee Titans all have positive scoring margins. The superbly coached, well-balanced Colts don't do much wrong and have far better Super Bowl odds at Caesars, the feisty Jags have won four of six games with a talented defense and a revelation at quarterback, and the Titans continually find ways to win and remain competitive. 

Houston's margin for injury was too low before Watt went down. This is a flawed team that already lacked consistency due to a shortage of depth on defense and poor pass protection on offense. Its Super Bowl chances rested on several key players remaining both healthy and productive. 

One of those key players was J.J. Watt. 

Brad Gagnon has covered the NFL for Bleacher Report since 2012.