Blaine Gabbert stole most of the attention following the San Francisco 49ers’ win over the Atlanta Falcons last week, but one could argue the defense played a more significant role in the final outcome.
With Matt Ryan at the helm and two of the league’s top playmakers, Julio Jones and Devonta Freeman, the Falcons boasted the 11th-ranked offense going into Week 9 even after struggling against some porous defenses in the preceding weeks. The Niners defense, of course, has been a sieve over the first half of the season, particularly versus top passing attacks, and came into the game with the second-worst defense in football by Football Outsiders’s opponent-adjusted metrics. To complicate matters further, San Francisco was without three starting members of the secondary responsible for allowing all of those big games through the air. On paper, it was set up to be an ugly day for the 49ers defense.
Unexpectedly, several young members of San Francisco’s defense proved to be up to the challenge, helping the 49ers put together their best performance since the season opener, per DVOA. The run defense limited Freeman to 12 yards on 12 carries. Marcus Cromartie, playing in his first action of the season after getting promoted from the practice squad a day before the game, held up admirably in place of Tramaine Brock at left cornerback. Jaquiski Tartt looked solid once again in his second start at Antoine Bethea’s safety spot.
One of the more intriguing performances of the day belonged to second-year cornerback, Dontae Johnson. It’s been somewhat of a strange year for Johnson. He showed promise while starting three games and playing 46.8 percent of San Francisco’s defensive snaps in 2014, yet found himself relegated to the bottom of the depth chart when the start of the 2015 season rolled around. Entering the Falcons game, Johnson had played in just 69 snaps (Nice), nearly all of which came in the first three weeks of the season. He nearly doubled that snap count in Week 9, taking the field for every one of San Francisco’s 64 defensive snaps.
As he has nearly every time he’s seen significant playing time, Johnson took advantage of his opportunity and put together a solid performance. According to data provided by Pro Football Focus, Johnson was targeted seven times, allowing four receptions for 56 yards while breaking up two passes. That works out to an 83.0 passer rating, coming in just below the league average passer rating (89.0) for quarterbacks in 2015. And really, the tape might have been more impressive.
Two of the biggest plays charged against Johnson were very similar, and together, they accounted for 38 of the 56 yards he allowed. However, it’s also difficult to fault Johnson too much for those plays.
Cornerbacks are generally coached to play with a certain leverage, either inside or outside, based on the routes they want to take away, what the rest of the defense is doing, and where their help is coming from. This idea is perhaps best explained by Pete Carroll while speaking at a coaching clinic during his time at USC (emphasis mine):
No matter what coverage you are playing you have to convince your players to win their leverage side. If the coach tells a player to play outside leverage and complains when a receiver catches a ball to his inside, the coach is wrong. When we give them a leverage side, we are telling them to just do that aspect right at least.
To take this even further for example we tell our corners to play inside leverage (i.e. to the inside shoulder of the receiver) in this defense. This helps the corner avoid giving up the big play to the inside of the field. If you want them to play the out route towards the sideline you have to give them someone playing support over the top. There is not a corner in college or the NFL that can both play the out routes and also avoid giving up the deep ball to the inside. You have to be realistic as to what your players can do. They only way a corner can play inside leverage and make a play on the out route is if the offense screws up or the quarterback makes a bad throw or the receiver runs a bad route. If you don’t understand that then you are asking the corner to do something he can’t do.
While a few of the very best cornerbacks might be able to excel in man coverage regardless of the route being run, coaches generally must choose whether they want the player to take away the inside or the outside. Understanding this concept, Johnson’s "worst" plays of the day don’t look so bad.
Johnson caught a lot of flack from the announcers on this play, as he gets his feet tangled up with Jones and takes a dive to the turf. However, even if he had been able to keep his feet, the dig route run by Jones isn’t one Johnson is being asked to take away. Eric Mangini has a Cover-3 variation called on this play, often called "Cloud," in which Johnson is playing with outside leverage and is responsible for the deep-third to his side of the field.
With that assignment, the dig route by Jones becomes the responsibility of one of Johnson’s teammates to the inside, most likely Michael Wilhoite. But the shorter crossing route by Jacob Tamme holds Wilhoite short and prevents him from getting enough depth on his drop to take away the dig, resulting in an 18-yard completion.
Midway through the fourth quarter, Johnson was charged with another big reception that came in a similar situation.
The seam route by Roddy White is attacking the same area of the field as Jones’s dig route in the previous play, which just so happens to be a weak spot in Cover-3 coverages. Johnson is once again playing with outside leverage in his deep-third responsibility and is looking to stay over the top of any deep routes, knowing that he should have help to the inside. But the help isn’t there. Wilhoite is again occupied by an underneath route. San Francisco’s safeties are attempting to disguise who has the deep middle, leaving Eric Reid to come all the way across the field to get there. White is able to take advantage of the resulting space for a 20-yard catch.
Remove those plays from Johnson’s sheet and it’s hard to find much fault with his game. He did a little bit of everything on the day, from playing outside to covering Jones and Tamme in the slot to even blitzing on occasion from Tartt’s old role as a Dime linebacker.
Unlike the previous two plays, here we get an example of what happens when Johnson is playing with the proper leverage to take away the route he’s facing. After motioning across the formation to create a bunch look to the right of the offense, you see Johnson in perfect trail technique, sticking to the inside hip of Tamme on the dig route.
Tamme might not be Jimmy Graham or Larry Fitzgerald, both of whom show up on the schedule following San Francisco’s bye, but Johnson was impressive when tasked with playing man coverage on the inside. At 6-2 with a 38.5-inch vertical, Johnson’s size also allows him to go up and challenge the receiver at the catch point, something he did twice when matched up with Julio Jones.
The first pass breakup came with Atlanta looking to attack the seam area of San Francisco’s Cover 3 defense, just as we saw in the first two plays above. The difference here was that, whether due to a tendency the Falcons had shown from this pre-snap alignment or just excellent post-snap recognition, Johnson is eyeing Jones up the seam from the very beginning. The high throw would spell disaster for most cornerbacks against Jones, who is as good as any receiver in football in jump ball situations. But Johnson plays it perfectly, climbing the ladder with Jones and winning at the catch point.
Considering the situation, one-on-one with Jones and Atlanta trying to take the lead with 3:46 to play, Johnson’s second pass breakup was even more impressive. The two routes Johnson must be prepared for here are the slant and the fade. His pre-snap alignment inside puts him in position to take away the slant. If Jones goes to the fade, which he does here, Johnson must recover and challenge at the catch point. His work here is textbook. He gets a solid punch to Jones’s inside shoulder, turns to find the ball at the goal line, and again prevents Jones from winning the jump ball situation.
We’re still working with a relatively small sample when it comes to Johnson’s body of work, but he’s been solid whenever given the opportunity. His skill set is relatively unique within the 49ers secondary. He’s the only cornerback on the plus-side of six foot, and his length and athleticism gives him a better chance of matching up with the bigger receiving threats on San Francisco’s schedule than someone like Brock or Jimmie Ward. There’s no guarantee Johnson would continue to play at this level if given a full-time role. But considering the extent to which the 49ers have struggled defending the pass, it’s hard to argue he shouldn’t see more playing time over the second half of the season.