Why Are Pro Day 40 Times Faster Than Combine 40 Times?


If you can’t tell by Matt Freedman’s numerous and informative bowl game writeups, draft season is nearly upon us. I know what you’re thinking – we just finished up the fantasy season and it was kind of nice to get back to normal life for awhile and not have to worry about fantasy football 24/7. But I’m also a step ahead of you. It’s a cold world out there, and boring too.

You need this. I need this.

I watched an episode of fucking House Hunters the other day.

You and I are a different breed. We’re like those Special Ops guys who end up doing like 3 tours in Iraq because we find normal life to be unbearable (the Special Ops analogy might break down if either of us is asked to do a pull-up).

So if we’re committed that we’re just going to feed this addiction instead of fighting it, then it makes sense to start talking about prospect workouts. Topic #1: Why do players run faster on average at their pro day than they do at the Combine? Actually I’m looking specifically at WRs in this case, so even if I refer to “players” going forward you should know that I mean WRs.

Of players that ran at both the Combine and a Pro Day, the Pro Day times were faster on average by about .03 seconds over the past 12 years. They improved their times from 4.54 to 4.51 on average.

The traditional answer to this question has been that Pro Days are essentially rigged in favor of the prospects. That could be partially true. But it’s not like the prospects are running on a faster track than they are at Indy. That’s a pretty fast track to start with. Another explanation is that measurement error at pro days comes out in favor of the prospects. The people running the stop watches err in the prospect’s favor. But I don’t think that is fully explanatory either. If that’s the case, why is there also an improvement in vertical leap? Verticals likely can’t benefit from the same operator error and yet among players that jumped at both the Combine and at Pro Days, the Pro Day measurements were close to 2 inches greater.

Here’s some summary information on Combine 40s that might help us. On average over about 12 years, WRs ran 4.50 in the 40 at the Combine according to NFL Draft Scout. Recall that I noted above that players that ran again at a Pro Day ran on average 4.54 at the Combine. I think that’s likely the answer for a good amount of the difference in Combine and Pro Day times. Players always are going to run in a range that they know about before the Combine, because they’ve been practicing. They go out at the Combine and for whatever reason they run at the slow end of their range. The players then have an option to run again at Pro Day, so they do.

To clarify a little, here are the averages for players based on whether NFL Draft Scout has a measurement for them at the Combine or at Pro Day.

*Averages Combine Time Pro Day Time
All WRs 4.50 4.51
Ran at Combine Only 4.47
Ran at Pro Day Only 4.51
Ran at Combine and Pro Day 4.54 4.51

So players that run at the better end of their range likely just let that time stand and don’t press their luck at a Pro Day. Players that run at the slower end of their range then know that the odds are that if they run again, they’ll improve their time.

Probably the interesting question here is whether we should be adjusting Pro Day times for prospects that didn’t have an option of running at the Combine. For either a player that wasn’t invited, or decided not to run, should we downgrade their time based on what we know about the difference in Combine and Pro Day times? I’m still thinking about that question and I don’t know if I have an answer yet.

By RotoViz Staff | @rotoviz | Archive

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