Jets defensive tackle Damon Harrison is a free agent, which leaves New York in a tricky position. According to Pro Football Focus, Harrison was the 7th-ranked interior defensive lineman, and the number one rated nose tackle. Not coincidentally, Harrison was rated as the single top run defender among all defensive lineman. As a result, he’s likely to command a pretty decent contract on the open market, and is also pretty valuable to the Jets.

On the other hand, Harrison was on the field for only 53.9% of all Jets defensive snaps in 2015. And given that the vast majority of Harrison’s value comes in the rushing game, and not the passing game, there’s a limit to the sort of contract he will receive. But what I wanted to highlight today is the interesting way in which the Jets have managed to get 8 years of strong run defense and great nose tackle play with a lot of moving parts. From 2008 to 2015, the Jets rank 3rd in yards per carry allowed.

In 2007, the Jets run defense was pretty mediocre; in ’08, the Jets traded a third and a fifth round pick ^[1]Which turned into Charles Godfrey and Gary Barnidge. for Kris Jenkins. That turned out to be a great trade initially, as Jenkins was an All-Pro caliber player ^[2]He was a Sporting News first-team All-Pro in ’08, and an AP 2nd-team choice that year. during his 23 games with New York, but injuries ended his career.

Given how dominant Jenkins was in ’08, it’s easy to assume the Jets run defense would have fallen off without him. But in his absence, Sione Pouha — a 3rd round pick of the team in ’05 who started just one game his first four seasons — turned into one of the game’s best nose tackles. He played very well in ’09 and ’10, and in ’11, Pro Football Focus named him the game’s top nose tackle.

A back injury ended Pouha’s season — and career — in 2012. In his place, Harrison took over and excelled. An undrafted free agent in 2012, Harrison beat out Kenrick Ellis to take the Jets starting nose tackle job. The man nicknamed Snacks has started every game for New York since, and provided excellent play against the run.

It would be optimistic, but probably naive, to assume that the Jets could just keep this up, and replace Harrison with an undrafted free agent that turned into a stud run defender. But it’s worth noting that New York has lost a number of strong run defenders — you can add Mike DeVito, Shaun Ellis, and Bart Scott to the list — and little has changed. Of course, David Harris has been a mainstay during this period, as has Calvin Pace, and both linebackers are best known for their run-stuffing ability. And the Jets managed to add some great run-stuffing defensive ends in Muhammad Wilkerson and Sheldon Richardson, too. That all makes Harrison’s job a lot easier.

Starting in ’08, the Jets have ranked 7th, 7th, 2nd, 4th, 15th, 2nd, 11th, and 1st (last season) in rushing DVOA. That’s impressive, given that runs through three different head coaches, three different nose tackles, and a host of players: only Harris and Pace have been on the team all eight years. Given how much the Jets have already invested in the defensive line, I don’t think New York can afford to give Harrison a massive contract. He would be a valuable player to keep, but not one the team has to keep. And given the presence of Wilkerson, Richardson, and 2015 first round pick Leonard Williams, New York’s run defense would probably remain a top unit without him.