Sunday, May 25, 2008

A Tale of Three DHs

At various points in late April:

- Jason Giambi was batting .109
- Jack Cust was sitting at .148
- Frank Thomas? .159 and picked up off the scrap heap.

Thomas, as you might have heard, was released by the Blue Jays, who claimed he wasn't good enough to start for them. Plenty of baseball writers were calling for Giambi's release, saying he was finished. As for Cust, he was declared a one-year wonder. Sentences like "You can't play in the Major Leagues with that strikeout rate" were written about him.

Were our three DHs (anyone who has seen Cust play the outfield knows he is a born DH) really finished as Major Leaguers? Let's take a look at their May stats:

Giambi: .333/.478/.667
Cust: .328/.471/.642
Thomas: .339/.425/.565

Now, none of these guys is a true .330 hitter, so each is playing well above his head. Still, that's a hell of a group of hitters right there.

A common misconception about regression to the mean is that a player who has underperformed up to this point will now begin to overperform until his aggregate season line reaches his established level of performance. That isn't how things work: we would have expected each of our DHs to post a May stat line more like .250/.375/.500. But no one should have sounded the death knell for any of these players based on 50 bad plate appearances.

It's a mistake baseball writers make every year. They should know better by now.

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