I’m sure I don’t have to say this, but without a doubt the hardest thing in analyzing any set of data is figuring out what role luck plays in its composition. Chance takes so many different forms that it can be hard to recognize, especially when it is so inherent in the nature of the game. Whether it’s a matter of a lucky guess on a swing, a chance gust that carries a fly ball over the wall, or one of those caught line drives that so frustrated Rod Kanehl, Lady Luck rears her ugly (to some) little head everywhere.
Last May, J.C. Bradbury, author of the fantastic Sabernomics blog introduced us to another tool for potentially culling luck from skill in an article at the Hardball Times. The statistic, which he calls Predicted OPS, or PrOPS, creates an expected OPS from the various components that help determine a player’s value at the plate:
With this model I can evaluate players by the process with which they reached these outcomes; thereby, hopefully separating useful information from the noise of raw statistics.
The model that best predicted a player’s OPS in 2004 included the following variables:
- Line drives per batted ball
- Groundball-to-flyball ratio
- Walk rate
- Hit-by-pitch rate
- Strikeout rate
- Home run rate
- Home park of the player
In the end, J.C. is left with what is really a component-OPS, similar to component ERA’s for pitchers. It gives us what we’d expect from a player who hits a certain number of flies, line drives, and groundballs. This is especially useful for checking out who is likely to see a decline or improvement in production due to a change in luck the next season.
That said, it should also be noted that PrOPS is not a prediction system, nor is it meant to be. It could certainly supplement any prediction system, but it does not include an aging factor. It just gives us more data to look at based upon what the player actually did with the bat, not just the results. It’s not that PrOPS predicts a player to improve or decline so much as it suggests that the player was playing at a different level than the conventional stats indicated.
I glanced over the Mets roster for next season and compared each player’s OPS and PrOPS. Here’s what I found:
Name OPS PrOPS Diff
Beltran, Carlos 0.744 0.729 -0.015
Castro, Ramon 0.756 0.739 -0.017
Delgado, Carlos 0.952 0.972 0.020
Diaz, Victor 0.797 0.771 -0.026
Floyd, Cliff 0.863 0.877 0.014
Franco, Julio 0.799 0.835 0.036
Lo Duca, Paul 0.714 0.755 0.041
Matsui, Kazuo 0.652 0.675 0.023
Nady, Xavier 0.760 0.766 0.006
Redman, Tike 0.625 0.671 0.046
Reyes, Jose 0.687 0.621 -0.066
Valentin, Jose 0.768 0.658 -0.110
Woodward, Chris 0.730 0.746 0.016
Wright, David 0.912 0.884 -0.028
The third column represents the net difference between OPS and PrOPS. A few numbers jump out. First of all, it looks like Paul Lo Duca played a little better than his OPS indicated last season, as did Tike Redman. While Redman hit so poorly that the 46 points he lost presumably to luck won’t make a huge difference, the bump pushes Lo Duca up to Mike Lieberthal territory–good enough to tie for fourth among National League regulars behind the plate.
The really interesting news is who over-performed their OPS, namely Jose Valentin, and Jose Reyes. Valentin, who didn’t have a great season to begin with, is looking older and older and may have difficulty escaping Spring Training. He’s worth a shot if he can rebound, and his winter numbers are good (.926 OPS), but looking at his PrOPS, I wouldn’t count on a return to form.
Jose Reyes, however, is a more troubling matter. Reyes was the thirteenth biggest overachiever in baseball last season, bad news for man who can only be said to have had a good offensive season for a 21 year old. As a comparison, former Mets sinkhole Rey Ordonez twice managed an OPS higher than that with the team. However, there’s still a question of what specifically happened to Jose last season to create such a discrepancy between his real and predicted values.
There are three main components to OPS: on base average, batting average, and isolated power (ISO). Obviously, Reyes’s terrible walk rates hurts him equally in OPS and PrOPS, so that leaves only the latter two. Turning our attention to his batting average, we have to wonder how likely it is that he will be able to keep up his .273 mark from last year. Reyes had a .300 batting average when he managed to put the ball in play, dead on the major league average. This means that Reyes did not enjoy any sort of special luck that artificially boosted his average due to lucky drops, grounders with eyes, or abnormally poor defense when he strolled to the plate. Even taking a closer look at Reyes’s batted ball data, he did not have any more hits than we’d expect from anyone else with his number of line drives, ground balls, and outfield flies.
That most likely means that Reyes outperformed expectations in terms of his power numbers, which at a glance certainly seems possible. The odd thing about Reyes is that his slugging percentage is so triples-heavy. In fact, triples accounted for 43% of his isolated power number, an unusually high percentage. It seems likely that PrOPS expects many of those triples to turn into doubles, singles, or outs. I, for one, don’t believe that all his triples are purely a result of luck, and there is some skill involved. Without knowing J.C.’s methodology exactly, it’s difficult to say whether he’s undervaluing hitters who may rely on the triple more than others, but it seems quite possible given their rarity. Looking at the list of overachievers, the list is dominated by speedy players like Ichiro Suzuki, Carl Crawford, Scott Podsednik, and Jimmy Rollins. Incidentally, the list of underperformers is dominated by slow catchers.
What do we draw from this? I think that just as there are some pitchers who consistently outperform their fielding-independent statistics, there are some hitters who will consistently outperform their PrOPS, and Reyes seems like a good candidate to be one of those players. Given that and the improvement we can expect as a result of his maturation, we should still see a fair improvement from Reyes. Or at least I hope so.