What Did Starlin Castro Gaffe Cost Cubs?

Last night everyone got nostalgic for 2011 or some similar bullshit, because WOW! DID YOU SEE STARLIN NOT HUSTLE?

This is the BIGGEST THING HAPPENING with the Cubs right now? Are we really going to hold this against the 24-year-old who just lost four of his best friends in a tragic accident last week?

Never mind that the mental lapses have been nearly non-existent this season.

Never mind that Starlin Castro has never once been on a good team, so we have no idea what his focus would be like in a playoff hunt.

Never mind that the team is in last place and on track for 90 losses.

No, it’s time to get worked up about Castro not hustling out of the box. So worked up that even folks like Len Kasper (who I love) are asking at which point do you cut Castro loose over such errors. As tedious as those conversations already are, let’s make this one even more tedious – by using math.

If you have exhausted so many sources of baseball content that you’ve found my writing, you’re familiar with run expectancies. If not – wow, welcome to 1997 or so – here’s basically how they work:

There are twenty-four possible combinations of runners on base and outs in baseball (eg. 1st & 3rd with 1 out). There are hundreds of thousands of instances of each base-out scenario in the history of baseball, and there’s data for how many runs have scored after each of those base-out situations.

Averaged out, you can find out how many runs you expect a team to score based on the current base-out scenario. It’s kind of rough, but over that kind of sample size it works really well. (This is also where the DON’T BUNT movement was born)

This brings us to last night. In the top of the 8th, Starlin Castro sent a booming shot off of the centerfield wall. He didn’t hustle out of the box, turning a sure double into a single. Instead of having runners on second and third with nobody out, they had runners on first and third.

The run expectancy for the former was 2.050 and the latter was 1.853, a difference of 0.197 expected runs. If that doesn’t sound like much, that’s because it’s not.

This is where we should stop. There’s no guarantee that the inning plays out the same way. If we’re being fair, we only judge the player based on what he did, not what someone else in the order did/would have done.

As a result, both the “game would’ve been tied” and “he never would’ve scored on the single” arguments aren’t useful here – we have no way of knowing what would’ve happened if he were standing on 2nd with a double, only how many runs were expected to score.

In that spirit, let’s look at the “double-into-a-single” baserunning gaffe in a totally context-neutral sense. Assuming Castro made that error in any situation, the change in run expectancy is about 0.17 runs.

This is what we’re trying to run Starlin Castro out of town over: 0.17 runs.

So, to answer Kasper’s tweet: at what point do you no longer put up with the occasional mental slip? Assuming once he’s below league-average he’s not worth starting and that he’s only about a win away from that, and at the going rate of about 9.5 runs/win, somewhere near the fifty-sixth time he does this in a single season.

Listen, I’m not saying we shouldn’t want players hustling – of course we should – but to get so worked up over this is not worth anyone’s time. We should keep an eye on this going forward, but please, let’s not act like this silly shit is why the team is bad.

Unless, of course, you’ve been trying to run him out of town for years. In that case then, by all means, don’t stop now

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