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What Kind of Passer Is Mitchell Trubisky?

I have mixed emotions when it comes to the Bears’ quarterback, so I went to the data in an effort to form an opinion on the kind of year Mitchell Trubisky has had to date.

New England Patriots v Chicago Bears Photo by Jonathan Daniel/Getty Images

The quarterback for the Chicago Bears has had some good games and some bad games, and he currently has a passer rating of 97.1, good for 14th in the NFL among quarterbacks with at least 53 attempts. That might seem like a strange cutoff, but it’s a number NFL Next Gen Stats determines by taking 15 attempts and multiplying it by the number of weeks of play, then dividing by 2. So, it’s basically a decent ballpark for “a quarterback who has played in at least half of the games so far,” but there will be some margin for error. Right now, 38 quarterbacks qualify. Being ranked #14 out of 38 isn’t bad, but passer rating only tells a very small part of the story.

Obviously, watching the game video is a great way of assessing a player, but two problems emerge. First, there’s the dreaded confirmation bias. Simply put, I will tend to see only what I want to see, or at least only what I expect to see. Second, there’s the fact that it’s easy to lose track of what other players do in similar situations. I notice that Trubisky misses an open receiver down the sideline, but I don’t have an honest sense of how many players actually do complete a similar pass in a similar situation.

My impression up until this point has been that Trubisky is doing better when Nagy sets him up as a game manager and that he’s missing some easy throws at critical moments, especially when he takes shots deep downfield. I was curious if the stats backed me up.

They don’t.

To be fair, the stats don’t disprove that impression, necessarily, but they also really don’t lend themselves to that sort of interpretation, either.

Let’s begin with my impression of Trubisky’s success being from more “game management” plays. Next Gen doesn’t have a game manager score, exactly, but they do have one interesting number that helps get a read on the exact opposite tendency. They track what percentage of each quarterback’s throws are into tight windows, defined as throws where there is a defender within 1 yard of the receiver at the time of the completion (or incompletion). Nearly one-fifth of Trubisky’s throws are into tight windows (19%). Only six quarterbacks are more “aggressive” than that, per Next Gen Stats. Of those six, only Ryan Fitzpatrick has a higher actual passer rating than Trubisky.

Likewise, Trubisky’s attempts are past the 1st down marker a lot. Next Gen keeps track of Air Yards to Sticks, which “shows the amount of Air Yards ahead or behind the first down marker on all attempts for a passer.” Trubisky is 6th in this regard, at +0.5 (just behind fellow sophomore QBs Patrick Mahomes at +0.7 and Deshaun Watson at +0.6) which matches both the aggression shown in the previous stat and my own sense of the number of times he takes deep shots down field, even if he doesn’t actually connect on those attempts.

However, two more stats are worth noting before moving on—Longest Completed Air Distance (how far the ball has traveled through the air in a pass) and Completion Percentage Above Expectation. That latter stat is a little complex, and it requires a lot of processing to even arrive at the score. Essentially, it measures how the passer’s actual completion percentage compares to what would be expected based on completion probability, or “the probability of a pass completion, based on numerous factors such as receiver separation from the nearest defender, where the receiver is on the field, the separation the passer had at time of throw from the nearest pass rusher, and more.”

Trubisky’s 60.7 LCAD is the sixth-highest among qualified passers, narrowly edging out Aaron Rodgers’ 60.3 LCAD. So, he actually can connect on bombs. However, are they the exception or the rule?

Strangely, despite all of my frustration with him, Trubisky’s +/- on Completion Percentage Above Expectation is +1.4%, good for 14th in the league. That number is worth repeating for clarity—compared to the average completion rating for the types of throws he is attempting, Trubisky is actually connecting on his passes slightly more often than would be expected. I don’t know enough about Next Gen’s raw data to tell you if he is more accurate to a degree that is statistically significant (my guess is he’s not), but even being functionally average in that regard is an improvement over the impression I have developed out of frustration.

Taken collectively, these numbers suggest that #10 is is pushing the ball down field into aggressive windows, and he not simply succeeding when Nagy limits the playbook. Instead, he is playing aggressive football, and he is doing it at a rate that is between 6th and 14th in the NFL. That’s actually really good.

Are some of these numbers padded by one really good game against Tampa Bay? Certainly. However, Trubisky has more than 200 passer attempts, and a number of his peers have also faced weak defenses, too. His passer rating has been “above” the average allowed by his opponents’ defenses on three occasions, and it has been below the average allowed on another three occasions. In short, he’s not simply a mediocre quarterback with inflated numbers from a single game. He is a growing quarterback making aggressive plays and accomplishing more than a number of fans expected from him.

Perhaps most importantly, he is not only playing well when the game is simplified for him, and he is not relying on wide open receivers to make plays on his behalf. Instead, Trubisky is looking more and more like a complete passer who just needs time to refine his craft.