Mariano’s pitch sequences and game theory

This is a nerdy subject, so I’ll keep it short and link-heavy. With pitch data freely available, we’re going to start seeing Game Theory used to analyze pitcher-batter matchups. Tommy at Beyond the Box Score touched on this earlier this week, and it’s a good read on pitch type game theory. Today at The Baseball Analysts, Dave Allen looks at Mariano Rivera’s pitch sequences. But, because Marino throws only one pitch, this sequencing deals with location rather than pitch type. An amazing non-game-theory note: Mo is insanely good when throwing to his glove side. Many pitchers have trouble controlling pitches on that side. Allen goes on to show how Mo fares when throwing inside to a lefty after an outside pitch, inside to a righty after an inside pitch, and so on.

As we know, Mo dominates lefties. He’s not quite as good against righties, and he’s particularly bad when going inside after an outside pitch — and is also not quite as good when going inside-outside. Tom Tango runs with that. In most cases with Game Theory, he says, we need to take the batter into consideration, because each batter has different strengths and weaknesses. With the outside-inside sequence, though, the difference is too pronounced to chalk it up to poor choices to certain batters. Mo throws this sequence 37 percent of the time (as in, throws an outside pitch 37 percent of the time after he throws an inside pitch). He would do well to cut down on that. Mo fares best against righties when going with the outside-outside sequence.

Just how long can you continue to throw righties outside cutters? I’m not sure. This is where longer pitch sequences would be helpful. For instance, if Mo goes outside-outside-inside, does he fare well? Or is that the sequence that hurts him the most? After all, he went inside after an outside pitch, which for him produces the worst result. But just prior to that he went outside after an outside. This also raises the issue of whether these sequences cover multiple batters. In other words, if Mo strikes out a righty with an inside cutter and opens the next righty with an outside one, is that counted as an inside-outside combination? Or are the sequences limited to single plate appearances? I would think you’d produce a bit of noise if you overlapped batters. Better to stick to single-batter sequences for these analyses.

This is the type of analysis that gets me excited. Even non-stat-heads can enjoy pitch sequencing and Game Theory. It’s an attempt to break down the most fundamental game in baseball, that between the pitcher and batter. Analysis doesn’t get any better than that.