Film room: How Khalil Mack and the Bears pass rush stifled the 49ers passing game and Nick Mullens continues to grow

The Bears came into Santa Clara for a Week 16 game with the 49ers in what is becoming an annual tradition in a storied rivalry. The two teams have met six times in the last seven seasons, splitting those games 3-3. The rivalry itself favors the 49ers 34-32-1, with the 49ers also boasting a 3-0 playoff record against Chicago.

The latest meeting featured a Bears team well on its way to making a deep playoff run sitting now at 11-4 and a 49ers team not quite able to find its edge yet with the obvious starters missing and on its way to their second losing season under head coach Kyle Shanahan. That didn't prevent the 49ers from making it a competitive game, however.

The score remained 9-7 in favor of San Francisco until late in the third quarter when the Bears were able to capitalize on a series of unfortunate events on their first drive of the second half. First it appeared that safety Marcell Harris had come up with a fumble by Allen Robinson after he stripped the ball from Robinson's grasp. Replay overturned the call as Robinson's knee had touched the ground.

Next, defensive lineman DeForest Buckner shot into the backfield, tackling running back Tarik Cohen for a loss only to be flagged for a facemask penalty that extended the drive. Instead of facing third and long, they got a fresh set of downs. The Bears would eventually score the go-ahead touchdown on that drive after a series of dink and dunk plays.

On the offensive side of the ball, the 49ers had limited success against the Bears' number one ranked defense, were only able to manage nine points off three Robbie Gould field goals, and were completely shut out in the second half of the game despite moving the ball decently on a couple of late game drives.

According to Pro Football Focus, Quarterback Nick Mullens was pressured on 17 of 39 dropbacks and completed eight of 16 passes for 70 yards, one sack, and one interception. Mullens was able to negate some of the pressure on his own but largely, it was the right side of the offensive line who failed him that day.

Overall, the Bears didn't do anything exotic to disrupt the timing of the 49ers passing game. According to Pro Football Focus, defensive end Khalil Mack had a total of 36 pass rush snaps and rushed an equal amount of times from the right and left, 18 each side. The difference was who he rushed against. Against left tackle Joe Staley, rushing from the right produced only three total pressures for him.

However, rushing from the left against right tackle Mike McGlinchey netted him three hits and two hurries, for five total pressures. In fact, the pass rushing productivity for edge defenders against McGlinchey was much better than when going against Staley.

Bears pass rush comes up big

Leading the way for the Bears in total pressures was none other than Khalil Mack, who according to Pro Football Focus, had eight total pressures (five hurries and three hits), the majority of which came against right tackle Mike McGlinchey.

In fact, the worst grades came from the right side of the offensive line with Mike Person and Mike McGlinchey, who posted grades of 57.4 and 44.3, respectively, in pass blocking. Person and McGlinchey gave up a total of 10 of the 17 total pressures while McGlinchey gave up four of the five quarterback hits.

Here on this play, the interior of the 49ers offensive line succumbs to the pass rush of the Bears Akiem Hicks (No. 96) and Eddie Goldman (No. 91). Both Hicks and Goldman just bull rush center Weston Richburg (No.. 58) and Mike Person (No. 68) into Nick Mullens' lap forcing Mullens into an off-schedule throw for a minimal gain to tight end George Kittle.

The Bears pass rush forced Mullens into several early and off-schedule throws, and he nearly completed a couple of them.

As far as pass blockers go, tight end George Kittle (No. 85) had the worst day in pass protection with a grade of 33.7. At the snap, Mack takes in an inside rush that does two things. First, he uses a "long arm" technique to prevent Kittle from getting any kind of leverage inside Mack's chest. As the technique suggests, the left arm of Mack controls Kittle's movement and rides Kittle into the throwing lane. To win the rush, Mack then uses a chop slip past Kittle and out leverages him into the throwing lane in front of the quarterback so Mullens has to release a bit sooner than he wanted.

The Bears pass rush did a good job of studying the recent tape on Mullens and his ability to move the pocket and create time to throw. On several plays, and on this play in particular, the Bears pass rush was able to create pressure up the middle and contain the edge, preventing Mullens from stepping up in the pocket or shuffling to create a throwing lane. Mack gets his rush up the middle and Mullens barely gets a pass off to receiver Kendrick Bourne down the sideline (No. 84).

Here on this play again, the Bears limit Mullens' ability to move the pocket or step up and make throws. Mack was again working against McGlinchey and rushes the outside shoulder of McGlinchey in the C-gap. McGlinchey has been solid in pass protection all season, but gets his feet crossed here by the more athletic Mack, who uses a "swipe" technique to get by and never recovers. Mack gets a free run at Mullens and gets the hit as Mullens releases a pass that falls well short of its intended target.

One way to slow down a pass rush is to throw short quick throws, screens, or use play action. The 49ers had some success throwing quick passes, but a team cannot make a living off those throws for an entire game and has to take its shots because a defense like the Bears will adjust and just won't succumb to the play action fakes or will be content to give up short throws.

Here on this play, Mullens executes a hard outside zone play fake and drops back to throw. Kittle motions over to the offensive right on a "sift" block to kick out Mack and McGlinchey has Hicks one-on-one in the B-gap. Kittle and McGlinchey partially collide in the backfield, enabling Hicks to move past an off-balance McGlinchey into the backfield. Mack oles Kittle as well and gets into Mullens throwing lane to disrupt the pass.

Later in the second half, the 49ers adjusted their pass protection to block Hicks and Mack with a three-on-two pass set but even then, Bears and former 49ers defensive coordinator Vic Fangio adjusted to account for that as well.

After an 18-yard pass play to Kendrick Bourne, the 49ers are near mid field and dial up another play action pass. Fangio quickly adjusted to his defensive linemen being double teamed with a fire zone blitz through the C-gap by rookie linebacker Roquan Smith (No. 58).

On the blitz, the line slants to the right and Mack takes an inside rush at the inside shoulder of Kittle, leaving the C-gap open for a blitz by Smith who gets the sack after running right by fullback Kyle Juszyzyk (No. 44), who doesn't get a chip on the linebacker as he runs right past him.

On the final drive, Mullens nearly fumbled the ball after he was hit during the throw. Replay reviewed the play and determined his hand was coming forward so there was no fumble but it was nearly a costly turnover.

But it wasn't his fault. McGlinchey put a bad rep on tape again and got beat inside again by Floyd who was working to the inside on the rookie tackle from a wide-9 technique spot on the defensive line. From the start, McGlinchey put himself on an island with Floyd. His vertical pass is an awkward series of mishaps created by several small crossover steps he takes to get in place to block Floyd.

This takes him off balance right away. Floyd engages McGlinchey and gets his hands and arms inside McGlinchey's reach, forcing McGlinchey to try and control Floyd from a less than ideal straight up-and-down base. From there it didn't end well. McGlinchey reestablishes his base, getting parallel to the line of scrimmage, but Floyd beat him inside anyway, getting to Mullens in time to disrupt the pass.

Nick Mullens has quietly good day

Quarterback Nick Mullens continues to drive his stock up, proving there is no chance that there is a battle for the number two quarterback next season, and could even create a little competition for quarterback number one. With Jimmy Garoppolo's future uncertain, it wouldn't hurt to have a viable number two who could come in at any time he's needed and carry the team in Jimmy's absence. One thing is clear, it doesn't appear there will be a spot for C.J. Beathard next season.

On the day, Mullens finished 22-38 for 241 yards, zero touchdowns, and one interception. That doesn't look or sound impressive, but against the Bears defense, he made several impressive throws, had one dropped in the end zone for a touchdown that Kittle should've held on to, and the interception (that should've been a catch) went off of Goodwin's hands late in the fourth quarter.

Still, Mullens gave his team chances it they needed them.

On the first drive of the second half, the 49ers faced a third-and-10 from their own 35 yard line. The Bears sent a "scoop stunt" to the offensive right with defensive end Bilal Nichols (No. 98) "long scooping" to the inside to occupy McGlinchey and the interior of the line. McGlinchey lets Nichols go when he sees the blitz in the B-gap by Danny Trevathan (No. 59).

The stunt and blitz combo leave Mack one-on-one with Mullens. Mullens has no chance to hit any other route in the progression at this point so he looks to running back Jeff Wilson Jr. (No. 41) out of the backfield on the "Texas" route. Mullens negates the pass rush from Mack on his own since the line wasn't doing it for him on that series.

He knew he was going to get hit so he pumped to slow down Mack just enough to get off a throw. He completes it to Wilson for a nine-yard gain, setting up a manageable fourth and inches that coach Kyle Shanahan ultimately decided to punt on.

While the Bears sought to minimize Mullens' ability to move the pocket, they could not always keep him contained within the confines of their front seven.

In what was perhaps one of the defining plays of the game, Mullens escaped pressure from his right and left as McGlinchey and left tackle Joe Staley got beat off the edge by Floyd and Mack, respectively. The two-by-two formation is running a stick-flat combination to the left with Kittle on the right inline running a "dino" route against a two-high safety look.

Mack gives a quick outside move before slapping Staley away and Floyd just speed rushes right past McGlinchey, forcing Mullens to vacate the pocket. Fortunately, he feels the pressure from Mack right away and slides to his left, scrambles out of the pocket and gets a throw off to Kittle. Kittle had a chance to come down with the pass but the defender stuck his arm in to prevent Kittle from controlling the pass. The 49ers really needed Kittle to come down with that one in such a tight game.

Regardless of the outcome of that pass, Mullens showed that his ability to move the pocket under pressure is one of his greatest assets.

Late in the game on the first drive of the fourth quarter, the Bears tried to confuse the quarterback with a simple fire zone blitz.

Floyd drops off into a shallow hook zone from the right side of the defense as Mullens comes off his first read, Kittle, and looks over to the left to the intermediate dig route from Bourne but it's well-covered. By now he has to scramble due to the pass rush.

As he scrambles, Kittle, running the deep out to the sideline, breaks back inside to the middle of the field as Mullens escapes to the right. Mullens sees Kittle is the only option on this play and to keep it going, he lets a pass fly to Kittle, which he does with precision across the field. Kittle catches it and gains 35 yards to get the 49ers into Bears territory.

Mullens' negative plays do not define him

Mullens' continued growth is a positive sign for the 49ers going forward in that they now have a viable back-up in case Garoppolo's recovery from knee injury does not go as planned next season. He made two late game mistakes that prevented any chance of the 49ers winning but they look to be mistakes that he won't make again.

The biggest mistake Mullens made happened on the play before the 4th down throw on the final drive. He had Kittle open across the middle on a hitch route here but threw the pass too high for Kittle to come down with. A completion definitely goes for a first down, and the next play likely doesn't even happen.

On the final play of the game, the Bears covered the 49ers receivers with man coverage. Not a single receiver could get separation for Mullens to deliver a pass. The pass rush eventually forced him out of the pocket where he was faced with a decision to either run or take a shot downfield. He chose the latter in a throw down field to Goodwin. The pass sailed out of bounds and left fans with 20/20 hindsight saying he should've run for the first.

Whether or not he could have is up for debate as it's very likely Floyd would've chased him down. Mullens released the pass about 13 yards behind the line to gain. Floyd was about four yards away so whether or not he could've gotten the first down is anyone's guess.

Mullens certainly thought he could've run for it, saying after the game that "I mean, I've just got to handle the situation better, I should have ran. I didn't run...I saw 'Quise down the field. Tried to give him a chance, instead of making the simple play. I didn't make the simple play."

After the game, Shanahan certainly didn't feel a need to rehash the play, telling the media in his post-game Monday press conference that "You don't have to rehash it very hard when you're dealing with a smart, honest dude who keeps it real and will admit it to you. Nick knows what he missed. By the time he came to the sidelines when I asked him, he already knew."

Whether or not he should've run for it on 4th down is a moot point now but one thing is certain: the 49ers have found their quarterback insurance for the foreseeable future, whether that means moving him in a trade for draft picks later on or as someone who can takeover for Garoppolo should his recovery not go as planned. Mullens will have one more opportunity to put some good plays on tape against a Rams team fighting for a playoff bye in Week 17.

Interesting fact

One thing I found while researching the history of this series was that the last touchdown the 49ers scored on the Bears occurred in 2015 in overtime when quarterback Blaine Gabbert found Torrey Smith down the sideline for a game winning touchdown on the road. The last touchdown at home against the Bears was in the first half of a 2014 game by legend Frank Gore. In fact, the last time Kyle Shanahan's offense scored a touchdown against a Vic Fangio defense was in 2011 when the 49ers and Redskins met in the nation's capital in Week Nine.

All gifs and images courtesy of the NFL.

All statistics courtesy of Pro Football Reference unless otherwise stated.