With Oliver Perez sitting in the mid-80s with his fastball, I scoured Fangraphs to figure just how many lefties can live at that velocity. Since it’s still March 4, I figured, being generous, there’s still some chance Ollie gets his velocity up to averaging around 88.
The following chart lists all the lefties who threw more than 40 innings last season with an average fastball velocity of 88 or lower. I included their HR/9 — which can be fluky across small sample size, for sure — and their BB/9, just to see if there are any good comps for Perez.
Perez has a career 5.1 BB/9 and a 1.4 HR/9. The only soft-tossing lefty that mustered any success while walking more than four batters per nine innings last year was Pedro Feliciano, and Perpetual Pedro benefited from a 56-percent groundball rate and career lows in home runs per flyball and home runs per nine innings.
All of the lefties who managed to have any success throwing 88 or below in 2010 either demonstrated good control or kept the ball in the park, or both. Obviously there are all sorts of caveats here — for one, some of these guys (like Feliciano) faced primarily lefties, which would improve their ERA+s.
Straight-up: Barring some sort of major adjustment, Oliver Perez would get straight-up rocked in a bullpen role. There’s absolutely nothing he can do at this point that Pat Misch — a soft-tossing lefty with great control — cannot.
Anyway, draw your own conclusions. Small samples at play.