Wednesday, February 25, 2009

The Stolen Base: Fallen From Grace

With the advent of the Juiced Era and an emphasis on sabermetrics by front offices around MLB, the stolen base has declined in use around the game.

One of the most telling disadvantages of stealing bases is measured by the run expectation stat. Below is the run expectation chart for the 2003 MLB season (thanks to writer Joe Sheehan at Baseball Prospectus).

Based on this chart, a runner on first with no one out is worth .9116 runs. A successful steal of second base with no one out would bump that to 1.1811 runs, a gain of .2695 expected runs. However, in the unfortunate event that a runner is caught stealing second base, the run expectation stat drops to .2783. This is a loss of nearly 2/3 of a run (2.3 times more than the gain).

Why would managers risk this chance for a run and give up one of 27 precious outs? Unless it is late in the game and there is a need for a tying run, the batter is a ground into double play threat, or there is next to little chance that the batter at the plate cannot drive the runner in from first (i.e. low slugging percentage), it is stupid.

Horrible times to steal bases include early in the game, when you need multiple runs (baserunners are important) and when a big slugger is at the plate.

In his article, Sheehan points out that the belief that running distracts defenses is misplaced or exaggerated. Sheehan correctly states that "a runner on first is more disruptive to a defense, with the first baseman holding and the second baseman cheating towards second for a double play, than a runner on second." He also points out the distraction that running has on the batter. How many times have we seen a batter give up an out by flailing at pitches in the dirt so that the runner can advance? If the batter strikes out and the runner is thrown out, the run expectation goes from .9100 to .1083 in an instant.

Sheehan concludes that break even rate for a stolen base is a 75% success rate. Thus, players with less than a 75% success rate should not even attempt to steal. In fact, if your speed is your only asset and you have less than or barely a 75% success rate, you shouldn't even be on a roster (ahem, Scott Podsednik).

Stealing bases also presents injury risks. Why risk the injury of high-salaried slugger such as an A-Rod, Vladimir Guerrero or Alfonso Soriano? The benefit that these players provide at the dish is immensely higher than their base stealing benefits.

With the decline in Performance Enhancing Drugs and subsequently the decline in the number of home runs, it will be interesting to see if the number of stolen bases returns to 1980s levels when Rickey Henderson, Vince Coleman and Rock Raines ran wild. Having a few .390+ OBP/85+% SB guys can make a team lethal so long as they are in front of a few power hitters. However, as evidenced by the teams mentioned in Sheehan's article, teams shouldn't run just to run.

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