How Much Does Mario Williams Have Left in the Tank?

When Mario Williams chose the "family atmosphere" (and nine-figure contract) the Buffalo Bills offered, it was an upset victory: One of the smallest, coldest markets in the NFL wooed one of the most sought-after free agents in NFL history.

Bleacher Report wasn't the only outlet to compare the Bills landing Williams with the Green Bay Packers' epochal 1993 signing of eventual Hall of Famer Reggie White.

Williams didn't quite have White's impact, but 43 sacks and two Pro Bowl nods in four seasons made him one of the most successful big-money free-agent signings in recent memory.

He has been released from his hefty contract, and right as a host of applied franchise and transition tags have taken most of the hot free agents off the market, Williams is again a big fish in a small pond.

But at 31 years old, 10 seasons removed from being the No. 1 overall pick, Williams is approaching the age when pass-rushers begin to rely less on natural talent and more on veteran wiles. With his poor fit in Rex Ryan's scheme, Williams had just five sacks in 15 games in 2015—tying his mark from 2011, when he was healthy for just five games.

How much does Williams have left in the tank, and how can he help your team?

Bill Wippert/Associated Press

Williams is still a rare combination of size and athleticism. Listed at 6'6", 292 pounds, Williams shows good get-off, change-of-direction ability and vertical leap. Though he has a well-earned reputation as a pass-rusher, he looked better as a run-stopper in 2015.

In Ryan's defense, Williams had a complex set of reads, keys and even coverage responsibilities.

"I'm not saying that the scheme is wrong," Williams told ESPN's Josina Anderson. "I'm just saying that our strengths could be utilized better. ... In our meetings defensively, especially in our defensive line room, we said, 'Can we go straight? Can we just go? Can we turn it loose?'"

Against the run, Williams was able to pick a gap and attack, and the result was a lot of disruption.

Check out the following play against the New York Giants. Williams (in yellow) has diagnosed this run and will attack the B-gap. The tackle will engage him head on, and the guard will come in to chip:

Credit: NFL Game Rewind

At the snap, Williams knows exactly what he wants to do: He gets his arms over the tackle and gets incredibly skinny in the gap. A man who weighs nearly 300 pounds should not be able to twist himself this skinny, at high speed, while his feet are still square:

Credit: NFL Game Rewind

It was hard to get a still that would reveal this, but after Williams gets through, Giants tailback Andre Williams is already almost past him. Mario does a jump-stop, lashes out a giant arm like Spider-Man shooting a web and slows the runner almost to a stop.

As the rest of the Bills descend on the tailback, he's driven back for a loss.

It's an impressive play very few ends could make. But they don't pay run-stuffing ends the eight-figure salary Williams will command, and it's here we have questions.

When Williams was able to work against lesser right tackles, his speed and handcraft were more than enough to generate pressure off the edge. But he often struggled to close unless helped out by a blown protection or poor quarterback decisions like this one from Blake Bortles:

Against bigger tackles, like the Dallas Cowboys' Doug Free, though, Williams' size and strength advantages were neutralized. He wasn't often able to win with straight speed, either, and here's where the speculative element comes in.

From his second season (2007) through 2014, Williams averaged 12.14 sacks per 16 games. For him to be worth the kind of money he'll be asking, he'll need to deliver a similar rate over the next two or three seasons.

In the three years leading up to 2015, Williams had 38 sacks despite lining up at both 4-3 defensive end and 3-4 outside linebacker.

The difference is he was able to sell out and attack the quarterback on pass-rushing downs. As long as the team that signs him is willing to take the leash off and let him run, there's no reason he can't be a difference-making player on every down.

But while 23 different players have notched more than 12 sacks in a season at age 31 or older, per Pro-Football-Reference.com, seven of them are Hall of Famers. Only four have done it twice: Chris Doleman, William Fuller, Bruce Smith and White himself.

Williams has the talent to pull that off, but he may not be able to get there without an ideal scheme fit. 

Every free agent comes with an element of risk, and this is the risk whichever team signs Williams will have to bear.