Mention the name Jeffrey Kessler—a key figure in the Deflategate scandal after being hired as Tom Brady's lawyer and one of the most important men in recent league history—to various people around the league, and the response is, well, fascinating. 

A veteran player: "He keeps that a------ [Roger] Goodell in check."

League official: "He's undermining the game. He's ruining it."

Coach: "He gets players back on the field. I love him."

League official: "The worst. Scares me because he's so good."

Said former Raiders CEO Amy Trask: "He's a tenacious lawyer. He's smart. He has both helped and hurt the players and the game. He's not a hero or a villain. He's a lawyer. And he's not the only lawyer who could do what he does. If there was no Jeff Kessler, another lawyer would fill that void."

And that's the smartest point of them all. Kessler is brilliant, talented, nerdy and tenacious, but more than anything, he is filling a void—and that void is being the legal archenemy of Roger Goodell.

Goodell is a dictator has almost become a meme. He isn't one, but the narrative has stuck, especially among the players. To them and the union, Goodell is Ultron—and Kessler an Avenger.

To some in the NFL, Kessler is a meteor, crashing into the Earth—the bringer of gloom. Like the Goodell narrative, that also isn't true. As Trask said, the truth is much more nuanced.

The irony of Kessler's situation now is that he finds himself on the same side as an owner. During the lockout of 2011, Kessler and Brady (along with other star players) teamed to file suit against the league to rule the lockout illegal. Now, Kessler and Brady are again pairing, as the union is seeking an independent arbitrator to rule on Brady's appeal, instead of Goodell.

Kessler will basically run the union's appeal, which will focus on several main points. First, that the Wells Report lacks direct evidence. Second, that NFL Executive Vice President of Football Operations Troy Vincent should not have made the punishment decision; it should have been Goodell. Third, that this case is not, as one league source says, "unlike any other in league history" and that the punishment is arbitrary.

This passage from the union letter seems vintage Kessler:

Please be advised that the NFLPA and Mr. Brady intend to call both you and Commissioner Goodell as essential witnesses in the proceeding. You both will be called upon to testify about, among other things, the circumstances surrounding the purported delegation of disciplinary authority from Commissioner Goodell to you in this matter and the factual basis for that purported delegation. You also will both be required to testify about when you became aware of the Colts' complaints about ball deflation and what decisions and steps were thereafter taken to set up what may have been a "sting operation" to try to implicate the Patriots and Mr. Brady. The latter conduct would present an additional ground for setting aside the discipline imposed.

No, Kessler didn't write the letter. But the union strategy thus far has all the Kessler indicators: put pressure on the league by making Goodell sweat, do things in a high-profile manner, swing for the legal fences (go big or go home) and stay on the attack.

Here is how the next steps—with Kessler running them like a point guard—will probably play out:

Goodell has already taken care of one aspect by naming himself arbitrator. In all likelihood, the arbitrator, Goodell, will uphold the league's side (potentially mid-June).

The appeal is where things get truly interesting. Go back to Michael Vick and the dogfighting. Vick spent two years in federal prison, but Goodell only conditionally reinstated Vick. Why? Several sources have long said that Vick lied to Goodell about the true nature of his involvement in that horrible case.

Whether you believe the Wells Report is legitimate or not (and I think it is) is irrelevant. The NFL believes it is. So if Brady sticks to his story that he knows nothing about anything, Goodell will take that as lying and uphold the suspension.

If Brady comes in and tells the truth (as the NFL sees it), then Goodell could reduce or even throw out the suspension. But Brady coming clean (as the NFL sees it) seems about as likely as Patriots owner Robert Kraft inviting Goodell over for dinner.

That is where Kessler comes in. 

After Goodell's decision, likely upholding his own ruling, Kessler will probably follow the same pattern as he did in other recent high-profile cases, where frankly he phasered the NFL and its attorneys. In both the Ray Rice and Adrian Peterson cases, Kessler went to federal court, and both times he was successful getting the suspensions vacated. Executive Director of the NFL Players Association DeMaurice Smith called the overturning of the Peterson punishment "a victory for the rule of law, due process and fairness."

If Brady does sue, Kessler will have a much more difficult time beating the NFL this time around. One reason is because a judge that has been favorable to Kessler and the union, David Doty, is no longer hearing cases. Also, the Peterson case being overturned was the legal equivalent of Halley's Comet, as several legal experts explained to Ben Volin of the Boston Globe.

"There's definitely an uphill battle in getting an arbitration award overturned—it's nearly impossible, unless you can show bias," Shannon Liss-Riordan, a Boston employment and labor attorney, told the newspaper. "And I think it's going to be pretty hard to vacate an arbitration award based on the arbitrator being biased if the CBA allows for the arbitrator to be an interested party."

Kessler has been a fixture in the NFL going all the way back to 1992, when he represented Jets running back Freeman McNeil, who beat the NFL's salary restrictions—the first step to total free agency. Kessler was also part of the legal team that got the Bountygate suspensions eventually overturned. In 2000, he was the lawyer for Bill Belichick, who wanted to leave the Jets for the Patriots. Kessler helped to engineer a trade, and the Belichick Patriots regime was born—a dynasty whose legacy Kessler is now trying to protect.

I've only met Kessler a handful of times. The lifelong New Yorker and Columbia Law alum is physically the opposite of many of the clients he represents. He's not a big man, is bespectacled and looks more like a college professor than one of the most feared litigators in sports.

What Kessler lacks with physicality he makes up for in brain power. One league official begrudgingly admitted that Kessler is "super smart." In the union offices, he is admired for how he takes on the NFL with great fervor. One team union official called him "a hero for the players."

Lawyer Gary Roberts has represented the NFL and opposed Kessler in some cases. Said Roberts to CBS Sports' Jon Solomon last year: "[Kessler is] extremely bright, he's extremely aggressive. He's able to see things in ways that most people wouldn't think about, which allows him to develop legal theories and ideas that are sort of outside the box. That makes him a very feared opponent if you're on the other side."

Again, there are other lawyers who could do what Kessler does in taking on the NFL, but he's the one who chooses to. And in doing that, he has become one of the most influential figures in the history of the sport. That is not an exaggeration. He will be a significant portion of the chapter in NFL history books written on this era of NFL uber-punishment, and his involvement in the Brady case will only make his impact clearer.

Mike Freeman covers the NFL for Bleacher Report.