Oliver Perez: Who are you?

The stats on Oliver Perez:
Birth: August 15, 1981
Height: 6' 3"
Weight: 160 lb.

Debut: June 16, 2002
Career: 51-58, 4.48 ERA, 1.435 WHIP
2008: 6-5, 4.98 ERA, 1.472 WHIP

Here's the problem. That doesn't show that there are actually two different people named Oliver Perez. They look exactly alike, they talk alike, they do everything the same way...except pitch.

One day, you'll get the Perez we saw against the Yankees last week. 7 IP, 3 hits, 1 earned run.

Other days, we'll see the Perez who can't make it out of the first inning, allowing five hits and six runs in only 1-3 of an inning.

John Delcos has affectionately named him "Coin Flip." How fitting is that?

Any day, either of the Oliver Perez's could show up. Hopefully, today, against the Phillies, we see the good Perez. The one who triumphs over evil and doesn't stink on the mound. We shall see.