Play-by-Play: Just how good was CJ Mosley in last year's season opener?

The big-money acquisition of linebacker CJ Mosley was supposed to be transformative for the Jets defense. For three quarters, it was. The defense played disciplined football, came up with multiple impact plays and looked well on the way to an impressive win over a team that ultimately went to the playoffs. Mosley was in the middle of that effort.

Unfortunately, Mosley suffered a groin injury late in the third quarter which not only ruined the Jets' afternoon, but also their season.

Buffalo, who had trailed 16-0 when Mosley was injured, kicked a field goal at the end of that drive and then scored two fourth quarter touchdowns against a Mosley-less defense that suddenly looked frail and error-ridden to win 17-16.

The injury was initially downplayed as Mosley was expected back soon. But a week became a few weeks and then several weeks and eventually cost him the entire season other than a one-off appearance against New England where he clearly wasn't healthy so they shut him down again.

Surprisingly, the Jets still managed win seven of the 14 games Mosley missed. However, you have to wonder how many more they could have won with him healthy.

It seems so long ago, we thought it would be worth running it back to that Bills game to remind ourselves of the contributions Mosley made on that day.

We're going play-by-play with our notes in italics after each play where relevant. This includes the part of the game after Mosley went down, for ease of comparison.

Josh Allen pass complete short left to Cole Beasley for 8 yards (tackle by C.J. Mosley)

Dropped into zone coverage and came up to make the tackle after a pass that was dropped in between Harvey Langi and Darryl Roberts underneath

Josh Allen pass complete short left to John Brown for 13 yards (tackle by Trumaine Johnson)

Blitzed, picked up by the left tackle with the pass released quickly

Penalty on Darryl Roberts: Neutral Zone Infraction, 5 yards (no play)

Josh Allen pass complete short middle to John Brown for 9 yards (tackle by C.J. Mosley)

Deep drop in zone coverage, made immediate tackle on pass completed in front of him with Neville Hewitt the closest defender.

Josh Allen pass complete short right to Patrick DiMarco for 4 yards (tackle by Jamal Adams)

Went to blitz but the QB threw immediately to the flat

Josh Allen pass complete short left to Cole Beasley for 10 yards (tackle by Darryl Roberts)

Blitzed, but not at full speed as he was likely tasked with containing Josh Allen. The right guard picked that up as Roberts lost Beasley on a whip route.

Josh Allen pass incomplete deep right

Drop into zone coverage. Pass thrown away under pressure with nobody open.

Josh Allen sacked by Jordan Jenkins for -12 yards. Josh Allen fumbles (forced by Jordan Jenkins), recovered by Steve McLendon at NYJ-38 (tackle by Jon Feliciano)

Drop into zone coverage. Allen hesitates as Jenkins beats the left tackle cleanly.

C.J. Mosley 17 yard interception return (Kaare Vedvik kick failed)

Josh Allen pass complete short left to Patrick DiMarco for 5 yards (tackle by Jamal Adams)

Deep drop, pass dumped off to flat.

Josh Allen right end for 3 yards (tackle by Jamal Adams)

Dropped to left flat to cover running back. Allen sees it's not open and tries to run the other way instead.

Josh Allen pass complete short middle to John Brown for 10 yards (tackle by Darryl Roberts). Penalty on Trumaine Johnson: Face Mask (15 Yards), 15 yards

Delayed rush around the edge, again at half-speed presumably with contain responsibilities. Pocket holds up for completion over the middle.

Josh Allen pass complete short middle to Cole Beasley for 6 yards (tackle by Leonard Williams and Neville Hewitt)

Another deep drop down the middle. Pass thrown underneath.

Josh Allen pass incomplete deep left intended for Zay Jones

Stayed at home underneath in zone coverage.

Josh Allen right end for 4 yards (tackle by Jamal Adams)

Another deep drop in the middle of the field. Allen keeps and runs for the first down.

Penalty on Jon Feliciano: False Start, 5 yards (no play)

Josh Allen pass incomplete short right intended for Cole Beasley

Another deep drop, with the pass thrown to the other side.

Josh Allen left end for 4 yards (tackle by Leonard Williams and Darryl Roberts)

Drops off and picks up Beasley, the inside slot receiver, and stays with him as Allen extends the play.

Josh Allen up the middle for 8 yards (tackle by C.J. Mosley and Tarell Basham). Penalty on Jon Feliciano: Taunting, 15 yards

"Collisions" the tight end as he goes to pick up the running back in the flat, then reacts to the scramble and comes up to make the stop shy of the marker to force a punt.

Josh Allen pass deep left is intercepted by Marcus Maye at NYJ-44 and returned for 23 yards. Penalty on Darryl Roberts: Defensive Holding, 5 yards (no play)

Possible blown coverage here as Trumaine Johnson dropped off into zone but the outside receiver ran into the space behind Mosley who wasn't dropping off. However, as Mosley tried to recover back into the play, Marcus Maye picked up that assignment and jumped the route for a pick (albeit that it didn't count).

Frank Gore up the middle for 1 yard (tackle by Henry Anderson and Jamal Adams)

Lined up close to the line of scrimmage and threw the tight end down at the point of attack to help bottle up the run.

Josh Allen pass complete short right to Dawson Knox for 1 yard (tackle by Trumaine Johnson)

Stayed at home in zone coverage. Quick pass thrown to flat.

Josh Allen pass incomplete short left intended for Devin Singletary

Looked to blitz but Allen threw an immediate pass that was dropped.

Frank Gore up the middle for 9 yards (tackle by Neville Hewitt)

Blocked off from making the play in the hole as the right guard immediately peeled off a double team on Steve McLendon. Still fought to get in on the tackle.

Frank Gore left guard for 1 yard (tackle by Steve McLendon and Leonard Williams)

Play stopped at the line before the left guard could get to Mosley at the second level.

Josh Allen pass complete short middle to Cole Beasley for 8 yards (tackle by Trumaine Johnson)

Blitzed around the edge and recorded a knockdown on Allen who made the completion under pressure.

Josh Allen pass complete short right to Cole Beasley for 8 yards (tackle by Darryl Roberts)

Quick pass to flat as Roberts forced to drop underneath a rub route.

Josh Allen pass incomplete short right intended for Devin Singletary. Penalty on Mitch Morse: Ineligible Downfield Pass, 5 yards (no play)

Initially dropped off but then read the screen pass and got in position to make the play near the line of scrimmage but the pass was dropped.

Josh Allen pass complete deep right to Tommy Sweeney for 29 yards (tackle by C.J. Mosley)

Deep drop into the middle of the field and ranged over to make the tackle near the sideline after the touch pass over Johnson's head.

Josh Allen pass incomplete short left intended for Cole Beasley (defended by Jamal Adams)

Stayed home. Adams batted the pass at the line.

Josh Allen up the middle for 8 yards (tackle by Frankie Luvu and Neville Hewitt)

Dropped off to the right side. Allen's run stopped short of the marker with Mosley in position to make the stop if he had cut the other way.

Josh Allen up the middle for 1 yard (tackle by C.J. Mosley and Leonard Williams)

Credited with a stop on a quarterback sneak as he cleaned up when Allen's initial progress was stopped.

Josh Allen aborted snap, recovered by C.J. Mosley at NYJ-37 (tackle by Lee Smith)

Quick reaction to record his second turnover.

Josh Allen pass complete short left to Devin Singletary for 4 yards (tackle by Darryl Roberts)

Dropped off then ranged over to sideline ready to make the play if the back got past Roberts.

Josh Allen pass complete short right to Zay Jones for -2 yards (tackle by Trumaine Johnson)

Dropped to inside slot but Johnson blew the receiver screen up immediately anyway.

Josh Allen pass complete short left to John Brown for 28 yards (tackle by Rontez Miles)

Late pre-snap adjustment to get Jamal Adams to drop off to the flat and pick up the back who otherwise would have been open. However, Johnson gives a clean inside release and can't keep up on the crossing route.

Josh Allen pass incomplete short right intended for John Brown

Disrupts crossing route as the pass is essentially just thrown away under pressure.

Josh Allen pass short right (defended by Harvey Langi) intended for Zay Jones is intercepted by Neville Hewitt at NYJ-48 and returned for 4 yards

Blitz drives the center back and helps collapse the pocket as Henry Anderson deflects the ball into the air for the interception.

Frank Gore left guard for -2 yards (tackle by Brian Poole and Jordan Jenkins), safety

Run blitz gets picked up by the left guard but the rest of the left side gets overwhelmed.

Frank Gore right guard for 1 yard (tackle by Neville Hewitt). Penalty on Leonard Williams: Defensive Holding, 5 yards

Run stopped at the line before anyone could get to Mosley at the second level.

Devin Singletary left end for 20 yards (tackle by Marcus Maye)

Well blocked play sees Frankie Luvu fail to set the edge and Adams gets kicked out by the left guard pulling. Mosley takes a false step in the wrong direction and the pulling center angles him off from preventing the runner from getting down the sideline. Hustles back to get in on the stop.

Frank Gore left tackle for no gain (tackle by C.J. Mosley)

Josh Allen pass incomplete short left intended for Dawson Knox

Delayed rush. Pass thrown quickly and wide.

Josh Allen pass incomplete short middle intended for Cole Beasley. Penalty on Henry Anderson: Roughing the Passer, 15 yards (no play)

Deep drop and diving pass break-up, negated by weak penalty.

Josh Allen pass complete short left to John Brown for 11 yards (tackle by Darryl Roberts)

Disrupts tight end's route over the middle, but pass completed outside.

Frank Gore left end for -2 yards (tackle by Neville Hewitt)

Three separate linemen try to block Mosley at the second level as Hewitt is unblocked to make the play.

Josh Allen pass incomplete deep middle intended for John Brown (defended by C.J. Mosley)

Josh Allen pass incomplete deep right intended for John Brown (defended by Marcus Maye)

Mosley no longer on the field, presumably having injured himself making that play. Bills settle for field goal on their last play of the third quarter to make it 16-3.

Frank Gore left tackle for 7 yards (tackle by Neville Hewitt)

Devin Singletary left tackle for 23 yards (tackle by Marcus Maye)

Huge hole with Blake Cashman lined up on the other side, Adams cut to the floor and Hewitt driven back at the second level.

Josh Allen pass complete short right to John Brown for 14 yards (tackle by Trumaine Johnson)

Josh Allen pass complete short left to Tommy Sweeney for 6 yards (tackle by Darryl Roberts)

Devin Singletary left end for 12 yards (tackle by Jamal Adams)

Run bounced outside as both inside linebackers get caught inside.

Josh Allen pass complete short left to Devin Singletary for 5 yards (tackle by Blake Cashman and Darryl Roberts)

Devin Singletary right tackle for 15 yards (tackle by Marcus Maye)

Huge hole as Hewitt gets caught inside and Cashman gets cut to the ground at the second level.

Josh Allen right end for 3 yards, touchdown

Rollout and dive for the pylon, beating Langi and Anderson.

Josh Allen pass complete short right to Devin Singletary for 8 yards (tackle by Trumaine Johnson)

Cashman missed tackle in open space near the line of scrimmage.

Josh Allen pass incomplete deep right

Josh Allen left end for 8 yards (tackle by Marcus Maye)

Easy 3rd-and-2 conversion on a designed quarterback sweep with Cashman getting driven off the line by a tight end and unable to get off the block.

Josh Allen pass incomplete deep right intended for Cole Beasley

Josh Allen pass complete deep right to Zay Jones for 20 yards (tackle by Trumaine Johnson)

Josh Allen pass complete short right to Devin Singletary for -1 yards (tackle by Blake Cashman)

Penalty on Ty Nsekhe: False Start, 5 yards (no play)

Josh Allen pass complete short right to Devin Singletary for 12 yards (tackle by Frankie Luvu)

Both inside linebackers blitz and the back is completely uncovered in the flat.

Josh Allen pass complete deep left to John Brown for 38 yards, touchdown, touchdown. Penalty on Darryl Roberts: Defensive Pass Interference (Declined)

Frank Gore right guard for 1 yard (tackle by Jordan Jenkins and Leonard Williams)

Frank Gore right guard for 2 yards (tackle by Trumaine Johnson and Marcus Maye)

Frank Gore right guard for 2 yards (tackle by Henry Anderson and Neville Hewitt)

Conclusions

Mosley's biggest impact was expected to be in the running game. In fact, some doubters had been degrading his coverage abilities when the signing was made. However, the Jets actually had one of the best run defenses even without Mosley.

In the first game, Mosley's impact was again felt mostly in coverage. In fact, he only had one tackle and one assist within eight yards of the line of scrimmage - and both were on plays where he was unblocked.

In coverage, Mosley had the pick six and disrupted two after passes, as well as being in position on one other incompletion. It was interesting to note how often the Jets had him dropping deep, including on some Tampa-2 type looks.

His other contributions included a quarterback hit, a fumble recovery and a stop on a third down scramble to force a punt, whereas the only real negatives were a couple of plays that saw him blocked at the second level, including one where he might have been able to make the play if the defensive line occupied the blocker a bit better before allowing him to peel off.

When the Mosley signing was made, here was our view on where it would help most of all:

Williams is a coordinator who places a lot of trust into his middle linebacker to call his defense and may have identified that Williamson had issues with this role last season. Following a loss to New England in November, Williamson conceded that he needed to be clearer in communicating adjustments to his teammates and admitted he set the front wrong a few times. There were also multiple examples throughout the season of blown coverages in the secondary that seemed to be caused by communication breakdowns.

Mosley has fantastic instincts, is quick to diagnose plays and his Ravens teammates and coaches lauded his leadership and communication. If Mosley can improve this aspect of the Jets' defense, this could prove to be the kind of move that benefits the whole defense in addition to providing an upgrade at one position.

Clearly this was an issue at the end of the Bills game with run fits and blown coverages suddenly rearing their ugly head and factoring in on both Bills' scoring drives.

Mosley should be donning the headset again in September and hopefully will stay healthy all year to spearhead the Jets' defensive effort. On the strength of this study, he'll bring a lot to the table.

BONUS LINK: Our in-depth scouting report on Mosley