Data Entry: How the Bears Should Handle Mitch Trubisky

| July 28th, 2017

Ryan Pace and John Fox have quite literally gambled their careers on Mitchell Trubisky, so now the question becomes how they should handle his rookie season to give him the best chance of success going forward.

With that in mind, I looked at how teams handled the rookie seasons of the quarterbacks drafted in round 1 in the last 20 years. There were 55 QBs in the sample, but I removed the 6 drafted in 2016 and 2017 because it is too early to draw any conclusions about their career outcomes. This left me with 49 round 1 QBs between 1998 and 2015.

I loosely grouped each quarterback into either a hit (developed into at least a solid starter for several years) or a miss (failed to establish themselves as a solid starter) and then looked at two different factors: how much they played in their rookie year and how well they played relative to their peers around the NFL as a rookie (full data can be seen here). Let’s look at each factor and see if any trends can be observed.

Rookie playing time

The amount of playing time 1st round QBs saw as a rookie varied wildly. Some players didn’t see a single snap their rookie seasons, while others took every snap, with many players scattered at various points in between. Overall, I couldn’t determine much of a trend to indicate players who played more would turn out differently than players who sat and learned.

  • 8 of the 9 players who started every game their rookie season turned into solid starters – with poor David Carr being the lone exception.
  • But 8 of the 9 who started 13-15 games did not. I don’t think those extra few games make that much of a difference, and trends are scattered below that, with too much noise to make any conclusions.

Overall, 12 of 28 QBs (43%) who started for more than half of the season panned out, while 10 of 21 (48%) who started half the season or less did. That’s not really a meaningful difference.

In more recent times, having a rookie QB sit has been less common.

  • Only 9 of the 27 first round QBs in the last 10 years of the sample (2005-14) spent less than half the season as a starter.
  • 8 of 18 (44%) who started more than half the season in this time span hit, while 3 of 9 (33%) who started less than half the season did.

Despite the larger numerical difference, the small sample size here makes those groups basically indistinguishable; just 1 more QB in the group of 9 panning out would make those numbers completely identical.

Rookie performance

So it appears that how much a rookie 1st round QB plays doesn’t seem to matter much to how his career ultimately pans out. That means the Bears are free to sit Trubisky as long as they would like this year without worrying about stunting his development. But they shouldn’t worry about damaging his career by throwing him into the fire either.

If Trubisky does get some meaningful playing time, how predictive will his performance be towards the rest of his career?

To examine this question, I looked at passer ratings of QBs in the sample who spent at least 1/4 of their rookie season starting. The goal here was to have a large enough sample such that their performance could get a somewhat fair evaluation. Passer rating is far from perfect, but I chose that as a general metric to evaluate QB play in a simple manner. Because the average passer rating has changed significantly over the time of this sample, I looked at their performance relative to an “average” passer in their rookie year (the 15th best passer rating among qualified passers, since the NFL has had 30-32 teams in this time span).

It appears that rookie performance does have some predictive value for how their career will pan out.

  • 10 out of 14 QBs who posted a passer rating within 10 points of the league average QB turned into solid starters.
  • Only 6 of 21 who were worse than that 10 point differential did so.
  • The match got stronger as the sample size got larger; if you look at QBs who spent more than half of their rookie seasons as the starter, those numbers change to 9/13 and 3/15.

But again the NFL has changed a lot in the last 20 years, so I looked to see if the patterns hold when I narrow the sample size to only 2005-14, the most recent 10 years of this sample. It turns out the pattern did hold for players who started more than half of their rookie seasons.

  • 5 of 7 rookies who were within 10 points of the league average QB turned into solid starters.
  • 3 of 11 who were farther than 10 points from the average did.


If you’re one of those people who don’t like wading through all the details and just want the conclusion, then this is the spot for you!

Long story short, history says Bears fans shouldn’t fret whether Mitchell Trubisky plays all year, sits all year, or does anything in between as a rookie. That hasn’t had any impact on the career outcomes of 1st round QBs in recent history.

Assuming Trubisky does play at least half the season, however, we can get a decent idea of whether or not he’ll pan out by looking at his rookie passer rating. If he stays within 10 points of the league average, there’s a good chance he’ll at least be a solid starter. For the past few years, the league average passer has posted a passer rating in the low 90s, so that means Bears fans should be hopeful if Trubisky to be somewhere in the 80s this year.

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