Stealing Second With Runners On The Corners
by, 05-11-2012 at 10:12 PM (1669 Views)
I just listened to Denard Span short circuit a potential rally by trying to steal second base with runners on the corners and one out. He was caught. I wondered if that was an especially stupid decision.
It turns out, it's not that risky. Or at least it's not if you accept that a baserunner usually needs to steal bases about 2/3 of the time to be effective.
Generally, one studies something like this using Palmer & Thorn's Run Expectancy Matrix. It's a neat grid that shows, given a certain number of outs and people on base, the average number of runs that should score that inning, based on 75 years of major league games. It was published in The Hidden Game of Baseball by Pete Palmer and John Thorn. You can find it here.
Here's the numbers we care about:
1. 1.088 - That's how many runs a team on average would score with runners on 1st and 3rd and one out.
2. 1.371 - If Span would've stolen the base, that's how many runs the average team would've scored.
3. 0.382 - If he was caught, that's how many runs the average team would score.
So Span risked a gain of .283 runs if he stole that base, but a loss of .706 if he was caught. Converting those to percentages, if he steals that base 71% of the time, the team breaks even. That's not especially different than the 2/3 view that is the case for most base stealers. This wasn't especially risky.