Gregg Williams, C.J. Mosley
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C.J. Mosley has opted out of the 2020 season. The New York Jets defense won’t be able to survive another season without him.

Kyle Newman

Saturday afternoon, C.J. Mosley shocked the New York Jets and their fans by opting-out of the 2020 season. The star linebacker was expected to be the captain of the Jets’ defense and help lead a unit that ranked 10th in DVOA in 2019.

With him gone, Gregg Williams‘s job becomes that much more difficult. Williams is considered one of the best defensive coordinators in the NFL for a reason. He hasn’t coached a defense to a below-average DVOA since 2011. No matter what happens, he always seems to find a way to put a competitive defense on the field. The 2020 New York Jets may be his biggest challenge yet.

Without Jamal Adams, C.J. Mosley, starting-caliber cornerbacks, and starting-caliber edge rushers, the Jets defense lacks talent at all levels. Mosley could have patched some of the Jets holes but without him, the holes only grow deeper.

Mosley’s impact

Jets fans saw first hand what happens when Mosley leaves the field in 2019. The Jets were dominating the Buffalo Bills in Week 1 until Mosley’s ill-fated groin injury. The defense collapsed, they lost, and the rest is history.

When Mosley’s on the field, he’s an elite player. He’s been an All-Pro in every year of his career except two, 2015 and 2019. He didn’t play a complete game in 2019 due to injury. It just goes to show how valuable he is.

Mosley’s biggest asset is his strong run defense. Seattle Seahawks linebacker Bobby Wagner is likely the only better run defender at the position. Mosley topped 100 tackles in four of his five years, and 10 tackles for loss in two.

He’s also a stout tackler, never having double-digit missed tackles in his career. He’s a major reason why the Ravens’ defense was elite in the run game for years. The Ravens went from sixth in run defense DVOA in 2018 with Mosley in the middle to 20th in 2019 without him.

Mosley is also an under-appreciated cover linebacker. He’s not elite in this area. He was never going to line up all over the field and man up tight ends and running backs, but he was a smart player in zone coverage. He could lock down the middle of the field and force the quarterback to take notice of him. He’s had eight interceptions in the last four years.

Without him patrolling the middle, the Jets defense should have suffered in coverage in 2019, but it didn’t. The main reason why, Jamal Adams. With Mosley gone, Adams had to step up in coverage, and he did. He locked down tight ends and running backs and was the reason the Jets pass defense ranked as high as 18th in DVOA.

With Adams gone, the Jets no longer have someone to protect the middle of the field in Mosley’s absence. That effect will be felt when the Jets go up against George Kittle, Hunter Henry, Travis Kelce, Darren Waller, Tyler Higbee, and Austin Hooper in 2020.

That means Gregg Williams is going to have to be that much more creative with his zone coverages in 2020. He’ll likely have to rely heavily on young players like Ashtyn Davis taking on bigger roles than they otherwise would have needed to. That’s certainly going to play a huge role in what’s likely to be another disappointing season for the Jets in 2020.

Potential replacements

With Mosley opting-out, the Jets are likely going to hold a competition to replace him. They are deep at linebacker, but losing an All-Pro talent is always hard.

Avery Williamson is expected to take one spot, though he’s still recovering from a torn ACL. Opposite Williamson, will likely be one of Neville Hewitt, James Burgess, Blake Cashman, and Patrick Onwuasor.

All four players bring their own unique skillsets to the table. Hewitt is a solid linebacker who has NFL starting experience. He started 12 games for the Jets in 2019 in relief of Williamson and Mosley. He struggles mightily in coverage, but his run support is up to the task. If Gregg Williams asks him to play a similar role to the one he played in 2019, the Jets would likely be getting a starting-caliber linebacker.

James Burgess is a former UDFA who saw significant playing time for the first time in 2019. He started the year as the team’s fifth linebacker, but ended up starting 10 games for the Jets in 2019. Burgess brings a similar skill set to Hewitt, but without the consistency that comes from a long-term role.

Unlike Hewitt, Burgess doesn’t have a long track record of play as a starter or backup. He saw time in his rookie year in 2017, but despite nine starts, Burgess rarely saw the bulk of snaps at the position. That began to change at the end of the season and he was set to start in 2018 before an injury hit.

That injury cost Burgess his roster spot with the Browns. After getting significant playing time with the Jets in 2019 they have a better understanding of who he is. He’s a decent run stuffer, though not as consistent as Hewitt, and he’s absolutely horrendous in coverage.

Despite only playing in 10 games Burgess allowed 467 yards in coverage. He was targeted an astonishing 65 times in just 10 games, opposing offenses targeted him week in and week out. That huge weakness in coverage is why Burgess is likely to end up on the bench, but if he’s improved he could shock and steal the job.

Blake Cashman is the exact opposite of Burgess. He’s a poor run defender, in large part due to his size and multiple shoulder injuries, but he’s excellent in pass coverage. The former fifth-round pick was the Jets fourth linebacker in 2019. He had replaced Mosley in 2019 before an injury ended his season.

Given more time, it’s likely that Cashman would have acquitted himself well and shored-up the middle of the Jets defense in coverage. However, the Jets can’t afford to lose the help in run defense. With Jamal Adams leaving, the Jets are already suffering huge losses in run defense. They can’t afford to take another massive hit by replacing Mosely with someone who struggles in that area.

The early favorite to replace Mosley is his former partner, Patrick Onwuasor. The former Baltimore Raven has years of starting experience and acquitted himself well next to Mosley for a few years. He struggled in 2019, leading to him being benched, but his history shows that he has starting-caliber upside.

Onwuasor was excellent in coverage in 2017 and 2018 before falling off a cliff in 2019. It’s not clear what caused the decline, but if he can reclaim that previous success, he would fill the void that Mosley leaves in coverage.

While not a particularly strong run defender, Onwuasor is a sure tackler. he can make the plays that are in front of him and won’t be a liability to the team in run defense.

At the end of the day, Greg Williams and his staff will have a tough choice to make. They won’t get to see any of these players in live game action. This decision will be entirely based on practice and past tape.

No matter what decision the Jets’ staff makes, one thing is clear. The New York Jets have lost an irreplaceable player.

A contributor here at I'm a former graduate student at Loyola University Chicago here I earned my MA in History. I'm an avid Mets, Jets, Knicks, and Rangers fan. I am also a prodigious prospect nerd and do in-depth statistical analysis.