The Luckiest and Unluckiest Batters by xwOBA

Last week I posted an article about Chris Taylor and how I expected him to regress. I won’t get into that much detail here but I just want to look at the luckiest and unluckiest players of 2017.

The under-archiever leaderboard looks like this (copied from Baseball Savant):

1 Miguel Cabrera 0.382 – 0.322 0.060
Graphs
2 Mitch Moreland 0.371 – 0.335 0.036
Graphs
3 Victor Martinez 0.344 – 0.311 0.033
Graphs
4 Alex Avila 0.401 – 0.368 0.033
Graphs
5 Albert Pujols 0.326 – 0.294 0.032
Graphs
6 Kendrys Morales 0.358 – 0.326 0.032
Graphs
7 Brandon Moss 0.336 – 0.305 0.031
Graphs
8 Taylor Motter 0.288 – 0.259 0.029
Graphs
9 Alex Gordon 0.300 – 0.275 0.025
Graphs
10 Jose Martinez 0.411 – 0.386 0.025
Graphs

 

And here is the over-achiever leaderboard. Also in the top-30 are the mentioned Taylor, Jose Ramirez, Nolan Arenado and Javier Baez, among notable players:

1 Eduardo Nunez 0.275 – 0.348 -0.073
Graphs
2 Marwin Gonzalez 0.320 – 0.387 -0.067
Graphs
3 Zack Cozart 0.332 – 0.399 -0.067
Graphs
4 Mallex Smith 0.239 – 0.305 -0.066
Graphs
5 Jose Altuve 0.349 – 0.413 -0.064
Graphs
6 Dee Gordon 0.254 – 0.318 -0.064
Graphs
7 Scooter Gennett 0.312 – 0.374 -0.062
Graphs
8 Kevin Kiermaier 0.279 – 0.341 -0.062
Graphs
9 Charlie Blackmon 0.364 – 0.424 -0.060
Graphs
10 Ronald Torreyes 0.241 – 0.299 -0.058
Graphs

 

Now the question is whether it is really all luck. If you look at the unlucky leaderboard, it is pretty easy to see that many of them are slow as dirt. The over-achiever group has some average-speed players (for example Marwin Gonzalez), but also speedsters like Altuve, Smith, Gordon and Kiermaier.

Overall, the under-performers had a higher launch angle, higher exit velo, and a slightly but not significantly higher pull rate (thought that might be a factor due to the shift, but really wasn’t).

 

sprint speed exit velo launch angle pull%
under-performers 25.66 89.24 12.59 42.1
over-performers 27.98 84.04 8.49 40.89

 

Of course we don’t know whether those factors like low LA and low power, which are generally associated with worse hitting, are not correlated directly to the sprint speed. To test that, I looked at some sub-groups. When searching for harder hitters at lower LAs, I took EVs of over 89, paired with LAs under 9 (just eight players fulfilled that BTW). You get a slightly positive differential, which means slight under-performance, but only by about 18 wOBA points. Looking at soft hitters (below 85) with high LAs (<12 degrees), it does get more significant at a wOBA difference of 30 points.

Hard hitters with high LAs, however, only under-perform a tiny bit (about 8 points), so LA alone doesn’t really seem to make a difference. Hitting fly balls soft might be a factor that affects the under-performing, and very clearly speed does.

What we need to find out is how much of that is sustainable year to year. We do know that some pitchers have the skill to outperform their FIP, but for the most part pitchers who outperform their FIP will regress. Under or over-performing xwOBA might not be pure luck; there are factors which likely have an influence on that. Some of that might be holes in the xwOBA stat that can be fixed over time, and others might be caused by the player type. I think we need to do more analysis on the predictive value of xwOBA and the factors that influence it.

But of course one last thing needs to be said: Over-performing your wOBA is nice, but still, the overall production counts. Some of the over-performing hitters are still not good hitters (Gordon, Torreyes, Gennett), while some under-performers are good.



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Anon
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Anon

Don’t remember who it was, but one of the FG writers earlier this year did a piece on xwOBA and made the same observation you have: xwOBA really needs a speed adjustment. Even a cursory look at the leaderboard shows that fast guys overperform and slow guys underperform. If you look back at prior years, you’ll see much the same thing. It’s why Miguel Cabrera has underperformed his xwOBA by 25 to 60 points every year of Statcast.

Intuitively it makes perfect sense: xwOBA is based on the expected outcome for all hitters for a given velo/LA. But not all hitters are played the same. Speedsters force the infield to take a step in which limits reaction time. Sluggards let the infield play deep which increases reaction time. The same ground ball or low line drive is going to be a hit a LOT more often for the speedster than the sluggard at the extremes of the list.

I never really appreciated how true that is until I watched a DBacks/Tigers game earlier this year and the DBacks were playing Victor Martinez so ridiculously deep at 2b, he had no chance at a base hit on anything on the ground. None. Brandon Drury was literally not all that far in front of the right-fielder. Thing is, he’s so slow and pulls the ball enough (this was as a LH hitter in this PA) that even if he had mis-hit the ball and Drury couldn’t have made the play coming in, the SS was shifted over and would have been able to make the play coming over.

Personally I think we’re going to see more and more of the slow sluggers (especially the ones that pull the ball) get driven out of the game by shifting and defensive alignments. So many of those guys are so slow that you really don’t WANT them to bunt for a hit because they can’t run the bases at all. Once their averages start plummeting to the low .200’s, it’s going to be hard to justify keeping them around even with 30 HR.

35th and Not James Shields
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35th and Not James Shields

Dominikk85,

Thanks for the research and article. I don’t think I had fully thought thru, probably still a ways to go, the implication of the hitter speed variable in the xwOBA-wOBA stat.