The Value Of The Stolen Base

Over the course of baseball's history, five statistics had come to be regarded as the best for evaluating players. They were runs, batting average, home runs, runs batted in, and stolen bases. Now, over the course of the almost 150 years that baseball has been in existence as a professional sport, new ways of looking at players have been developed. Statistics such as OPS+, WAR, and rbat have changed the way that players are viewed now. In fact, sabermetric statistics have been a driving force behind dramatic increases of votes for the Hall of Fame. Players such as Bert Blyleven owe their induction in part to the sabermetric community.

Yet, despite the realization that a statistic such as batting average or RBIs no longer tell the true value of a player, stolen bases persist in the imaginations of baseball fans. Why is this? This seems to be a two part answer. First, the stolen base is a lot rarer now than it was even twenty five years ago, when players such as Vince Coleman and Rickey Henderson were consistently at or near the century mark for a season. Second, the stolen base is one of the statistics that count in majority of fantasy leagues, which make players such as Jacoby Ellsbury or Juan Pierre appear more valuable than they are.

Using the win probability statistic, it was determined that from between 1999 and 2002 a stolen base added .018 wins. That is 1.8% for those of you that cannot do math. Meanwhile, a caught stealing subtracted .043 wins, or added the probability of a loss by 4.3%. In order for a stolen base to actually add anything to a team's success, the runner needs to be successful on at least 70% of his attempts.

Meanwhile, a home run adds roughly 10% to a team's win probability statistic. While decidedly old school, Earl Weaver's famous reluctance to steal bases and wait for the three run home run was, in retrospect, actually quite ahead of his time for a way to view the game. The home run adds a lot more to the odds of a team winning than a stolen base does.

Taking the percentages above, let's say that the average major league starting position player hits 15 home runs. He would then add 150% to his team's possible victories. Meanwhile, Juan Pierre in 2010 stole 68 bases while being caught 18 times. This adds up to providing a positive of adding 77.4% to his team's projected ability to win a game. For Pierre to add as much as an average player, he would have needed to steal around 130 bases at the same success rate.

Players such as Pierre, Dexter Fowler, and others who do nothing more than provide speed are often overrated. Ellsbury fell into this category prior to this year, where he has suddenly developed a bit of power to go along with his 50+ stolen base potential. While the stolen base is an exciting play, it is easy to see why as baseball management has changed the way they evaluate players, the pure speed player is practically a dinosaur. Getting on base and being able to move the line along is more valuable than being able to steal 60 bases, but only get on base at a .330 clip, as Pierre did in 2006 (it was actually 58 bases, but the point is still there).

The way of evaluating baseball players has changed a lot. So too should our perceptions of what makes a worthwhile major league player.