Regression to the mean. It’s a buzz term in the world of baseball statistical analysis. The premise is that baseball is such a complex game that we’re bound to see outlying performances all the time. Eventually, after a good number of plate appearances or innings, a player’s numbers will start to resemble his true talent level. Sometimes that will involve a complete correction, in which a player performs worse than his true talent and the numbers even out at the end of the year. Other times the player will just revert to his true talent and his season will look a degree better because of the hot streak. Either way, the player eventually regresses.
(And, just to eliminate any confusion, regression don’t necessarily mean downward. A player who starts cold and brings his numbers up also regresses. In 2009 Mark Teixeira regressed after his April performance.)
At the beginning of the season the Yankees were receiving production from two unexpected players: Francisco Cervelli and Brett Gardner. While some were greatly optimistic about Gardner heading into the season, I don’t think anyone could have predicted his insanely hot start. Absolutely no one predicted Cervelli’s torrential production early on. These two Yankees make for an interesting storyline, especially considering what they’ve done lately.
Cervelli: The story of regression
Early in the season opposing pitchers just couldn’t figure out how to make Francisco Cervelli hit his dinks and dunks to fielders. Everything seemed to find a patch of grass, or the dirt between fielders. On May 14, after a 2 for 4 day against Minnesota, Cervelli was hitting .415/.583/.528. No one in their right mind predicted he’d maintain that level of production. Yet many bought into the Cervelli hype. He did, after all, hit .298 last season. Plus, only the strongest of heart and mind can avoid being seduced by his wine bar eyes. But because he had only 101 plate appearances last year, we never got a sense of his true talent level.
Since that day in May — after which, coincidentally, he took over catching duties full-time while Jorge Posada hit the DL — Cervelli has fallen hard. In 93 PA, which covers more PA than his early season hot streak, he is hitting .200/.315/.227. That, too, is not necessarily indicative of his true talent level, but it certainly is a correction of sorts. It has brought his season numbers down to a much more believable .282/.374/.344. If he hit that in 350 PA as the sometimes-starter, I think everyone would be satisfied.
The good news: he actually increased his walk rate during this span. It’s why his .200 BA hasn’t been absolutely awful during this span. Instead it’s been tolerably awful.
Gardner: Maintenance, my man
At the start of the season, if you’ll remember back that far, Joe Girardi actually platooned Brett Gardner with Marcus Thames in left field. That didn’t last too long, not only because of Thames’s atrocious defense, but also because of Gardner’s stellar bat. In his first 108 PA, ending with the Boston series in early May, Garnder was hitting .344/.425/.419. Again, this isn’t something anyone could have expected him to maintain, but even if he settled into his true talent he would have quite an impressive season.
What we learned since, I think, is that no one has a good idea of Gardner’s true talent level. In his next 95 PA he dipped a bit, hitting .250/.326/.333, but then he got hot again. A thumb injury has taken away some playing time, but it hasn’t affected his performance. In June he is 10 for 22 with five walks, two doubles, a triple, and a homer. That has brought his season line up to .317/.400/.422, so while that’s a bit lower than his peak, it hardly represents a severe regression.
Where will Gardner end? No one, absolutely no one, can tell you with any degree of certainty. Like most players he has hot and cold spells, so it’s tough to tell what’s real and what’s a hot streak. It does appear, however, that Gardner can be more than the fourth outfielder which many people pegged him as. If that’s the case, he might have saved the Yanks the millions they would have otherwise spent on Carl Crawford.
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