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Do Justin Fields’ Rookie Fumbles Portend a Fumbler? Data Says It’s Unlikely.

| May 17th, 2022


Despite only starting 10 of 17 games last year, Justin Fields fumbled the ball 12 times, which was the 4th highest mark in the NFL. That’s a real problem. Since fumble recovery is random, meaning you will lose roughly half of your fumbles, that’s an additional turnover around once every two games. Given the strong relationship between turnovers and game outcome, this is a recipe for losing a whole lot of games.

But is this a problem that is likely to continue for Fields? Let’s see what history might be able to tell us.

Fumbling Rookies.

It is surprisingly common for rookie QBs to fumble the ball. A lot. Since 2001, there have been 24 instances of a rookie QB fumbling the ball ten or more times. Looking at the rookies who have played the most, there are 61 rookie QBs in that time span with at least 250 pass attempts, and 22 of them (more than 1/3) had at least ten fumbles.

So, in that regard, Fields is in good company. While many of the QBs on that list went on to bust status, there were plenty of successful QBs as well, including Lamar Jackson, Andrew Luck, Derek Carr, Alex Smith, and Carson Wentz as long-time starters.

This led to a logical follow-up question: do QBs who fumble a bunch as rookies improve after that? In order to explore this, I tracked fumble rate through two methods:

  • Plays per fumble, which includes all pass attempts, sacks, and rushes. This is a measure of how often a QB fumbles compared to how often the ball is in his hands.
  • Hits per fumble, which includes all sacks and rushes as plays in which the QB got hit. This is a measure of how often a QB fumbles when exposed to contact with the ball in his hands.

I should note that this list only includes QBs who had 1000+ career pass attempts total, such that there was a large enough post-rookie sample size to gather meaningful data. This gave a sample size of 17, which includes over 8,000 rookie plays and 40,000 non-rookie plays.

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