There’s been a lot of hubub recently about the Detroit Tigers’ stolen base gap – specifically that they’ve stolen only 30 bases while opponents have stolen 105 bases against them. There was an article on Mlive today regarding this very thing. This is quite obviously not a good thing, but how bad is it exactly? How many runs has this cost the Tigers this season?
That’s a question that is probably very difficult to answer specifically, but it’s quite easy to an expected runs answer in a general sense. A specific answer is better if your question is framed in a specific historical context, but a general answer is just as good (if not better) if you really want an answer in terms of “true talent” or “what can be expected going forward”. It’s usually always the latter that I prefer.
Anyway, we can use the handy-dandy glossary section from FanGraphs and use their weighted stolen base runs formula to determine how many runs the Tigers are leaving on the table by (1) not being very good at stealing bases themselves and (2) not being very good at preventing opponents from stealing bases. Here’s what I came up with
|Team||SB||CS||Success Rate||wSB (runs)|
First things first: it’s not the frequency with which you steal bases that determines the value, it’s the success rate with respect to the frequency of attempts. A team could steal 200 bases, but if they got caught 500 times in the process this would not be good. In the same way, a team that steals few bases could provide positive value if they were quite successful in those attempts. Neither of those scenarios describes either the Tigers or their opponents, but I wanted to put it out there.
So it’s easy to see in the numbers that the Tigers have been easy to steal upon and have been quite bad at stealing themselves. It would be better if the figures were reversed, but even though the stolen base gap (for and against) is 75, we’re really only talking a 13 run differential. Every 10 runs is roughly equivalent to a win in baseball (there’s math involved there, but that’s really how it works), so the Tigers’ lack of success on both ends of the stolen base department has cost the team 1.3 wins so far. So maybe they’d be 78 and 54 right now instead of 77 and 55.
Another point to consider is that stolen bases aren’t an end unto themselves; it’s only part of the run scoring (and prevention) equations. Detroit is quite clearly bad on both ends, yet they remain both the top scoring offense (5.1 runs per game) in the American League (all of baseball, acutally) and the top run prevention team in the American League (3.8 runs allowed per game).
We can always point out the flaws in our team or ways to improve, but I think this is a relatively small deal. The Tigers have the best run differential in all of baseball, so they’re certainly more than making up for whatever they lack in the stolen base game.
Here’s what it comes down to: Closing the stolen base gap from -13 runs to zero runs would stretch their (already) AL Leading 1.3 runs per game differential to 1.4. I don’t see that as something to get all hot and bothered about.