Probability and Sunday Night Baseball

There’s nothing I like more than a bases-loaded, no-outs situation in baseball. This might be my favorite situation/stat no one realizes. There’s around a 15% chance that the team who has the bases loaded will not score at all that inning! 15% might not seem like much, but over the course of the season it happens often.

Let’s set the scene: Bottom of the ninth, down by two, the Pirates knock in a run and get McCutchen on 1st with no outs to move within one run of the Cardinals.

This is a win probability graph FanGraphs has for every game. I’m not entirely sure what all they consider when calculating a win probability, but it mirrors the data I have, so there’s not much to discuss there. Clearly, the closest they came to winning the game was after Barmes walked putting Alvarez, the winning run on 2nd.

source: FanGraphs

According my run probability calculations for 2013, the probability to score at least one run with bases loaded and no outs was lower than the Pirates batting with a runner on second/third or first/third and no outs [Probabilities –123: 77.9%, 1_3: 82.4%, _23: 90.9%] The advantage of having the bases loaded is a walk or HBP brings a runner home, but the downside is there is an easy force at home. That would hurt the Pirates in this instance because Mercer didn’t hit the ball past the pitcher’s mound making for an easy 1-2-3 double play.