Speed Adjusted Slugging (aka, SaSlg) is a stat we’ve devised here at AVSG to use when comparing two players when speed/stolen bases is a major component of one player’s game but not of the others (for example, comparing Albert Pujols to Andrew McCutchen).
SaSlg (S-A-Slugging) is “normal” slugging adjusted for stolen bases & grounding into double plays. It’s calculated like normal slugging, but instead of total bases divided by at bats, SaSlg is (total bases + stolen bases – caught stealing*2 – double plays grounded into)/at bats.
The idea is that a player that can “turn singles into doubles” with stolen bases has an “effective” slugging higher than his traditional slugging would indicate. On the other side of the equation, a player that gets caught stealing or hits into a double play has lost his team an additional base (by either turning a single into a caught stealing or turning the baserunner into an out) that a faster player might not have.
We’re not the first to suggest something like this, I’ve seen others put forth similar ideas (most recently by Henry Druschel over at Beyond the Box Score, but alsohere, here and, but none of those have really caught on. Also, most of them don’t really account for the true effect of getting caught stealing (that it’s costing the team two bases, not just one) and most (all?) ignore the effect of hitting into double plays (or, to look at the other side of the coin, the benefit of a player who doesn’t hit into double plays).
In a lot of the time, this stat isn’t going to be all that different than “regular” slugging. And in cases where the two players have similar speed profiles (e.g., Adam Dunn & Jim Thome) the effects will largely cancel each other out. However, when comparing a speedster player to someone whose speed rates just above a three-toed sloth, the difference is noticeable (and meaningful).
Comparing a Speedster to a Statue
For example: In 2014, Mike Trout won the AL MVP with Victor Martinez placing second (in a unanimous vote for Trout). On the surface, Martinez seems to have the better stat line: Trout hit .287/.377.561 with 36 HR and 111 RBI and Martinez hit .335/.409/.565 with 32 HR and 103 RBI. Martinez’s slash line definitely looks better than Trout’s, with a much higher batting average (2nd in the majors) and on-base percentage (also 2nd in the majors). He also had only 42 strikeouts to Trout’s MLB-leading 184 (For a good portion of the season, Martinez had more HR than strikeouts, a very difficult feat historically speaking).
However, if we also consider Trout’s speed (and V-Mart’s lack of speed), the “on-field” effect of that slash line shifts a bit. Trout stole 16 bases while getting caught only twice (he’s been a very high percentage basestealer for his career) and hit into only six double plays. Martinez, on the other hand, stole three bases and was caught twice and hit into 17 double plays (Martinez, a catcher turned DH has never been a speedster – in 2006 he hit into 27 double plays, Trout’s current total for his now 4+ year career).
Adjusting for this, Trout’s SaSlg is .571 while Martinez’s SaSlg is .532, a gap of almost 40 points. Again, this is just one stat among many, but it is a way to explicitly quantify the argument “well, you’ve got to remember that a single and a stolen base is basically a double” in a controlled manner. It also allows us to better compare players whose offensive contributions differ significantly because of speed and baserunning.
What About the Pure Speed Players?
This is also an interesting way to evaluate players for whom speed is their primary contribution. A great example is Reds outfielder Billy Hamilton. As Grantland’s Jonah Keri notes, Hamilton is currently stealing bases at a 1980s pace and is doing so at a very high rate of success – currently 88%, well above the league average of roughly 70% (Hamilton is also the subject of Druschel’s article linked above). The problem with Hamilton is that stealing bases is about all he’s doing and you can’t steal first.
Because of this, Hamilton has a slash line of .220/.269/.287 with only 19 walks (v. 48 strikouts) and 10 extra-base hits on the year. That’s a horrendous line for an MLB starter and gives him a wRC+ of only 52 (i.e., 48% worse than league average). That said, if we adjust for his speed, his 44 SB (against 6 CS) and only 2 double plays grounded into turn his league-low .287 slugging into a far less embarrassing .391 SaSlg which would put him about #100 in the majors (and roughly league average). Still not great, but at least serviceable.
In Hamilton’s case, his rancid on-base percentage (10th from last in MLB) keeps that speed from being of much value, but if he were to improve to league average (even a bit short of it), his speed and defense would make him a useful MLB starter.