During Saturday’s Pirates-Nationals game, pitcher Matt Chico came to the plate with a runner on first (Paul Lo Duca) and one out. The score was 2-1 Nationals in the bottom of the second inning. Chico fouled off the first pitch swinging. The Pirates announcers were absolutely shocked that Chico was not bunting the runner up to second base. They could not imagine why anyone would even question making the call to bunt.
However, Manny Acta was displaying his knowledge of the game, instead of relying on “the book.” In order to show why this was a smart move by Acta, we will ironically turn to a book called, The Book, written by Tom Tango, amongst others. This book uses statistical tools to reevaluate “the book.” Gathering the rule from The Book, it states “With a pitcher at the plate with one out and a runner on first, only the worst-hitting pitchers should bunt, and even then, only about half the time.” Chico has a career batting average of.167, but this is with only 60 at bats. So, it would not have been a terrible move to bunt him, but swinging away was probably the more attractive option.
To break the rule down, the Run Expectancy for when a pitcher sacrifices in that situation is .326. On the other hand, when an average-hitting pitcher swings away, the RE is .354. With one of the worst-hitting pitchers swinging away the RE is .318, but rises to .325 if you account for the infielders being in. In other words, whether one of the worst-hitting pitchers bunts or swings, the outcome is about the same. Since Chico is better than the worst hitting pitchers, it would be better, on average, to have him swinging in this situation.
What was the outcome in real life? Chico showed bunt on the next couple pitches, taking them for balls. This kept the infield charging. On the fourth pitch, he sent a sharp grounder past Adam LaRoche at first base, placing runners on the corners with still only one out (a RE over 1.00). The Nationals left the inning up 5-1 and went on to a 9-8 victory. Kudos to Acta for going against “the book” and relying on The Book.
Cross-posted at my blog.