SLG

From Wiki Gonzalez

SLG is Slugging Percentage (Total Bases / At Bats), the lesser component of OPS.

SLG is one of the few old-time baseball statistics (along with ERA) that has made a smooth transition to the sabermetrics era as a respected measure for comparing players. For example, ISO (Isolated Power) was derived from SLG and Batting Average by Bill James as a way of evaluating a player's raw power.