Mitch Trubisky, Do We Have a Problem? (No. Not yet.)

| June 10th, 2019

I’ve been doing a deep dive into Chicago’s offense from a variety of perspectives, and want to wrap that up today with a closer look at Trubisky. I’ve already written about him several times this offseason, talking about:

Today I want to look at how wildly his performance fluctuated with the caliber of defense that he faced. Honestly, this was not the article I set out intending to write. I first did this research with the hypothesis that Trubisky did better in early games – when there was less pressure from a national audience – and struggled in primetime games where more people were paying attention. Just watching those games, it always looked to me like Trubisky was tense, like he was putting too much pressure on himself and thus not performing well. It seemed to me like he was more relaxed in early games that got less attention, which enabled him to just go out and play.

And there might be some truth to that; Trubisky posted a passer rating of 114.4 in early games, 89.9 in late afternoon games, and 63.0 in night games. But two of the four night games (Green Bay and Seattle) came in the first two weeks of the season, when Trubisky was just not comfortable in the offense yet. He was awful in an afternoon game against Arizona the next week too before breaking out in Week 4.

I then noticed that the other two night games – when he also struggled mightily – were against the Rams and Vikings, two of the better defenses the Bears faced all season. In fact, those were statistically his 2 worst games of the year, with 3 of the next 4 bad ones being the 3 weeks before he broke out. And thus a different hypothesis emerged, and I started exploring how well Trubisky performed against good and bad defenses.

As you can see in the table below, the difference is night and day. I split defenses up based on the passer rating they allowed.

  • The top 10 pass defenses by this metric were in the 70s or 80s, so I grouped those as good defenses.
  • The bottom 7 were above 100, so they are grouped as bad, and the middle tier in the 90s is grouped as around average.
  • This split up Trubisky’s throws pretty nicely, as every group featured at least 4 games and 125 pass attempts.

You can see Trubisky’s performance in a variety of metrics, with numbers in parentheses indicating how that compares to the average against those defenses.

Notice here that Trubisky absolutely demolished bad pass defenses but performed below average across the board against anybody who was average or better. In particular, he threw too few touchdowns and too many interceptions in those games. And it wasn’t like 1 or 2 bad games did him in; of the 9 times Trubisky faced average or better defenses, he finished with a better passer rating than the average the defense allowed only 3 times, with only 1 of them 10+ points above average, and 5 times his passer rating was more than 10 points worse than the defense’s average.

I think a somewhat optimistic yet realistic look at this data is that it highlights two things about Trubisky:

  • His pure physical talent. Look at those numbers against bad defenses. Even after you account for the caliber of the defense, Trubisky was still way better than average in these 5 games. Basically the only game when he didn’t crush the other team was against Green Bay in week 1. This shows what Trubisky is capable of when he can just play and use the gifts he’s been given.
  • How raw Trubisky still is. For as great as that one row is, the other two are equally ugly. This shows what happens when better defenses can take away exactly what Trubisky wanted to do and force him to play a more refined and nuanced game that relies on mental processing and technical refinement. He simply wasn’t there yet last year, which is understandable given his lack of experience in that offense and in general.

These splits are certainly cause for concern, but I don’t think there’s any need for panic – yet. Last year we saw glimpses of how good he can be, but plenty of reminders of how far he has to go. Now in 2019, the glimpses need to start becoming more of the norm. This is year three as an NFL starter and year two in the same offense with the same targets. Trubisky should be mentally far enough along at this point that he can better handle what a decent defense throws at him, which means we need to start seeing him putting up big performances against more than just terrible defenses.