Stealing bases in 2009

Just for fun, I figured I'd check the breakeven percentages for basestealing in 2009, and I came across a startling discovery, which I'll come to later.

When deciding whether to steal, one must weigh the risks against the rewards. If one steals successfully, there is a base gained, which is nice, but you still have to have some offense do something. If the runner is caught, then not only do you lose a baserunner, but you also lose an out. Further, there are situational issues at stake too. If you steal a base in front of a guy who is going to hit a home run, then you gain nothing except fantasy points. If you get caught stealing in front of a guy who is going to hit a home run, you lose a run. When the batter is a patient line drive hitter, stealing bases can be more advantageous. In general, though, you can look at a nifty little tool that Baseball Prospectus has on its website called the Run Expectancy Matrix. From this, you can determine the break-even percentages, defined as the percentage of stolen base attempts that need to be successful in order for the attempt to have been worthwhile. Here are the breakeven percentages for each scenario:

Stealing second, runner on first only

0 out: 70.1%
1 out: 73.3%
2 out: 69.4%

This is the most standard stolen base situation. Your leadoff guy reaches and is the only one on, often a speedy fellow. You want him to be successful about 3/4 of the time at least, and in 2009, that was actually a little more than enough. All about getting something going with a guy in scoring position.

Stealing second, runners on first and third

0 out: 76.6%
1 out: 79.2%
2 out: 92.8%

This is a much stricter standard than stealing with a runner on first only. Why is that? Well, there is a runner in scoring position. A base hit will yield a run, and even a flyout will with less than two outs. Further, one should figure that if you've gotten runners on first and third, you've been getting to the pitcher pretty effectively already. Holding onto precious outs would be more important now. Especially with 2 outs; if caught with 2 outs, you risk losing a chance for a dinky little single to score you a run.

Stealing third, runner on second only/runner on first and second:

0 out: 83.3%/76.9%
1 out: 67.8%/71.4%
2 out: 87.0%/87.3%

Having a runner on second with nobody out can come from either a double, a single/walk followed by a wild pitch, balk or steal, or an error throwing to first. In any event, it reflects that your opponents are having a tough time with pitching and/or defense, and you should not ruin that too early. With one out, though, it's a huge dropoff and I don't know why. Presumably a runner on 2nd with one out more often corresponds to a single/walk followed by a bunt or some other productive out, or suggests that the pitcher is a bit more adept at getting batters out, and the sac fly is probably not a bad way of trying to get a run across. Again, stealing with a RISP is not a good idea with two outs. Adding the runner on first makes this a bit more worwhile with nobody out though not as much so with nobody out, but is still a bad idea with 2 outs. It's still better to try to steal third with 1 out, for some reason.


Double steal, runners on first and second catcher throws to third (default)

0 out: 60.0%
1 out: 54.9%
2 out: 81.0%

Can you believe how much more valuable it is to have the guy behind you try to steal too? This doesn't factor in the weak possibility of a double play on a double steal attempt. But still, most players can achieve that kind of stolen base percentage, so the double steal is really not a bad idea. The tail runner doesn't appear to be as important since it always makes more sense to attempt to throw out the lead runner, particularly with nobody out. One has to think you try this more with a right-handed hitter who's not a big power guy up, like Russell Martin or Orlando Hudson.

Double steal, catcher throws to second

0 out: 45.4%
1 out: 54.9%
2 out: 81.0%

This is something that just won't happen unless the catcher screws up. But it could happen, and it helps to be successful here. It could also happen if the third baseman was caught completely off guard or is just really poor defensively, or if the catcher feels more comfortable with the second baseman backing up the shortstop, or if you know the tail runner is a lot slower or got a much worse jump. Still, this has to be a split-second decision, so don't expect your opponent's catcher to do that.

In any event, the double steal should be much more popular than it is. Baseball Prospectus looked at it a couple years ago, and many managers are more risk averse with this. One would assume it's because they want to make sure both runners are good basestealers, and most teams don't always have a pair of guys who can do that.