There are a lot of new stats out there that paint very nice pictures of just how good a batter is. But, for all the awesomeness of WAR (Wins Above Replacement) and wOBA (Weighted On Base Average), they still have one flaw that we see in most stats. That is, they don’t tell you who is getting the hits when it matters most*.
That’s where WPA (Win Probability Added) comes in.
WPA isn’t necessarily an indication of how good a batter is, or how good they will be in the future (that’s where WAR and wOBA come in). Rather, WPA tells us how important a player’s contributions have been.
In short, at any given point in a game, a team has a probability of winning the game. In the first inning it is about 50 percent. If the Rays are winning by 12 runs in the 9th inning, that chance is 99.9 percent.
WPA tells how much that percentage changes from one play to the next. For example, if a player hits a home run in the 9th inning when the Rays are already winning by 12 runs, the WPA is not very much (that home run doesn’t mean much). But if the player hits a 3-run home run in the 9th inning when the Rays are trailing by two, the WPA would be huge (that home run is much more important). At the other end, if a player hits into a double-play in an important situation, that would be a negative WPA.
Think of it this way: if a player does something good (a basehit, stolen base, etc.), they will earn more points if it happens during a critical moment in the game. And if the player does something bad (strikes out, doesn’t get the runner over, caught stealing, etc.) they lose more points if it happens during an important part of the game.
First up, the hitters, here is their overall WPA…
Matt Joyce has been the most important bat in the lineup so far. His offensive production has contributed to 2.21 wins on the season. He is followed by Johnny Damon and Casey Kotchman. At the other end, Reid Brignac has killed the Rays offensively (unlike WAR, WPA does not consider defense).
Think of this as the guys that have helped the most or hurt the most. But there is a problem. Obviously, some players have more opportunities. Like RBI, much of a player’s success depends on how many opportunities a player has.
So let’s scale the WPA per 100 plate appearances and see who has made the most of their opportunities. For this, we eliminated the players with only a few plate appearances…
WPA per 100 PAs
Joyce is still the leader, although now we see that Kotchman has actually made more of his plate appearances than Damon.
We also see that Evan Longoria, has made a positive impact with his bat, but even if we scale it, he is just the fourth best hitter on the team this season. And that is not good.
But what about BJ Upton. To get a better sense of Upton, we need to tease the data a little bit. Remember, we are adding up all the good and the bad plays. What if we separate the good and bad.
Here is each player’s WPA+ (sum of all their good plays, in blue) and WPA- (sum of all their bad plays, in green). Subtracting the bottom number from the top number would give us the player’s total WPA…
WPA+ and WPA-
If we add Upton’s positive plays we get 7.20 WPA. That is second only to Damon, and considerably higher than most Rays. But if we add up all of Upton’s negative plays (baserunning is included), he has the largest WPA- (-5.97) on the team.
In other words, Upton has been the Rays second-most important bat, and the bat that has hurt them the most.
And really, is that surprising? Upton does a lot of good things. And he does a lot of boneheaded things. The net result is that Upton is just the fourth or fifth best hitter on the team even though he leads the team in both home runs and stolen bases.
Again, this doesn’t necessarily tell us who the best hitters are. But it does tell us who has been the most important in the first half.
Now if we could just figure out a way to get rid of evil BJ.
All data via Fangraphs.com
* Clutch is a bit of a controversy that many authors have proven to not exist. My own thoughts are that clutch is real, but that it is different from what most people consider “clutch.” I don’t think players get better in the clutch. But I do think there are players that are better at maintaining their normal ability. That is, some players get nervous in the clutch and suck. The players that are able to remain calm don’t get better, but it seems that way because other players don’t remain calm. Think of it like giving a speech in public. Some people get scared and can’t talk normally. Those that don’t get scared don’t talk better in public. But they are able to talk normal. To me, that is clutch.