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The Trubisky Deep Ball Should Improve

| March 7th, 2019

This is part of a series of collaborations between film guru Andrew Link of Windy City Gridiron and stats guy Johnathan Wood of DaBearsBlog. We’re excited to be working together to bring fans of both sites great content by combining our approaches.


Last time, we identified deep passes as the main thing Mitchell Trubisky struggled with in 2018, and broke down film to see why that happened. Despite making up less than 25% of his pass attempts, 75% of Trubisky’s interceptions came on deep balls, and his completion percentage on those throws was well below the league average as he missed a lot of open targets.

This week, we want to again use stats and film to see why that may or may not improve going forward.

Highly Variable

To approach this from a statistics perspective, I used the Pro Football Reference Game Play Finder to break up raw passing statistics into:

  • Deep (15+ yards down the field)
  • Short (<15 yards past the line of scrimmage)

I looked at 19 quarterbacks who were starters in 2018 and had been playing consistently for at least 4 years (full data here). I’ll note that data for deep passes only goes back through 2008, so that’s as far back as I was able to go for QBs who have played longer than that.

Here’s what I found: while some quarterbacks are certainly better deep passers than others, the amount of year-to-year variability for each quarterback is greater for deep passes than short passes. That can be measured through the standard deviation for each quarterback, which expresses how much they vary from year to year in a given statistic (bigger number = more fluctuation). I found this for each quarterback for the main passing statistics, both short and deep, and then averaged them for all 19 quarterbacks in each category. The results can be seen in the table below.

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