Modern Baseball Statistics (Part Two: Base Running)

This is part two of a series of articles I’m writing to introduce some of the newer statistics announcers are using in broadcasts. Last time I covered Park Factor and how it affects hitters. This time I’m going to discuss BsR. BsR is a base running statistic created by Fangraphs. I’ll get the formula out of way and then breakdown the components.

BsR = wSB + UBR + wGDP

wSB stands for weighted stolen bases. It estimates the number of runs a player contributed to or took away from his team by stealing bases. I won’t get into the formula for this statistic, but a player’s stolen base percentage is important. A success rate below 67% will result in a negative number for this statistic. For example, a player stealing 9 out of 10 bases is more valuable than a player who steals 20 out of 40 bases.

UBR is ultimate base running. It is for non-stolen base plays. It estimates the number of runs a player contributed for doing things like going from 1st to 3rd on a single. Tagging up and advancing on an out. It penalizes for not advancing or getting thrown out. Basically, this is the smart base running measure. UBR data started in 2002, no data is available before then.

wGDP is weighted grounded into double plays. This measures the ability of a player to avoid hitting into a double play. It doesn’t include line drive double plays. So mostly this is a measure of a player’s speed or ability to not hit the ball on the ground with a runner on first.

Before we discuss some players here is a table from the Fangraphs site to give you and idea of what the numbers for a single season would mean.

Rating BsR

Excellent +8

Great +6

Above Average +2

Average +0

Below Average -2

Poor -4

Awful -6

Here is a list of a few players with their career BsR numbers:

BsR Career Years BsR/Yr

Player #1 144.4 25 5.7

Player #2 100.4 23 4.4

Player #3 96.0 18 5.3

Player #4 35.3 10 3.5

Player #5 -76.6 20 -3.8

Players #1 and #2 are in the Hall of Fame. Players #3 and #5 will both likely be elected once they are eligible. Player #4 is second on the Mariners all-time list for BsR.

Player #5 is David Ortiz. He is fourth worst all-time for BsR. I wanted to add a well-known player with a large negative score for context. Player #4 is Julio Cruz, a good base stealing second baseman for the Mariners in the seventies and eighties. Player #3 is Ichiro. He is the Mariners’ BsR leader and he is third on the BsR all-time list. Ichiro’s best year for BsR was in 2006 when he posted an 11.3. Like most players his numbers were better during the earlier portion of his career. Player #2 is Tim Raines who had 808 stolen bases at an 84.7% success rate. Player #1 is Rickey Henderson, who remarkably never had a negative BsR season in a 25-year career. I saw him late in his career, in a Mariner uniform, steal a base after the Oakland A’s thought they had caught him in a rundown.