Quickie: Dallas Braden's Perfect Game May 11, 2010
Posted by tomflesher in Baseball.Tags: Baseball, Braden's perfect game, Buehrle's perfect game, Dallas Braden, Oakland As, probability, sabermetrics, Tampa Bay Rays
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Dallas Braden of the Oakland As pitched a perfect game Sunday, on Mother’s Day. Under the methods discussed last year after Buehrle’s perfect game, Braden – who’s been active for four seasons – has an OBP-against of .328. That means he has a probability for any given plate appearance of .672 of the batter not reaching base.
Since he sat down 27 batters consecutively, the probability of that event happening is (.672)27, or .0000218; equivalently, given his current stats, a bit over 2 in every 100,000 games that Braden pitches should be perfect games.
Over the same period (2007-2010), the American League OBP has hovered between .331 (this year) and .338 (2007). .336 was the mode (2008, 2009), so I’ll use it to estimate that the chance for a perfect game facing the league average team would be (.664)27, or .0000157, or equivalently about 1.5 out of every 100,000 games should be a perfect game.As you can see, it’s more likely for Braden than the average pitcher, but not by much.
Nice job, Dallas!
As a side note, the Tampa Bay Rays were the victim of BOTH perfect games. Their team OBP was .343 in 2009, with a probability not to get on base of .657, meaning that the probability of getting 27 batters seated consecutively is about 1.2 in 100,000. Since many other teams have lower team OBPs, it’s very surprising that the Rays were the victims of both games.