Let Him Rest
Early in Friday night’s SNY broadcast, a stat was flashed up showing that Mike Pelfrey has an 0-5 record, 8.59 ERA on regular 4 days’ rest, and 7-4 with a 3.91 ERA with 5+ days’ rest.
Gary Cohen commented — correctly — that those stats did not jive with traditional sinkerball pitchers. The theory is that a pitcher who relies on a sinkerball — as Pelfrey does — tends to be more effective when he’s “not strong”, because a “tired arm” will throw pitches with more sink. There’s some logic behind this: a slower pitch will indeed have more downward movement, because it is decelerating at a more drastic rate than a faster pitch as it continues forward. When a sinkerball pitcher is “too strong”, his ball will tend to stay on constant plane, rather than “die” as it approaches the plate (it’s all about physics, folks).
However, knowing what kind of Pelfrey is right now, the stats make sense. Generally speaking, a pure sinkerballer throws in the mid- to high 80s, topping out just around 90. Old-school sinker specialists such as Tommy John, Rick Reuschel, and Randy Jones fit that mold, and current groundball specialists Chien-Ming Wang, Aaron Cook, Derek Lowe, and Jake Westbrook are good examples of pitchers who would benefit from throwing a few MPH slower.However, all of those hurlers — and sinkerballers in general — relied or rely on a mixture of sinkers and offspeed pitches to keep batters off balance. In contrast, Pelfrey more closely compares to Brandon Webb, who is something of an anomaly — a sinkerballer who has “giddyup” on his fastball, occasionally touching 93 MPH. Peflrey throws even harder than that, with some guns clocking him at 96-97+.
But here’s the thing: when Pelfrey’s sinker is working, he’s throwing it in the low 90s — which makes sense; any faster and it wouldn’t sink. The problem is that his slider — a.k.a. his offspeed pitch — is around the same speed, maybe 3-4 MPH less. That’s not enough to keep a batter off-balance.
However, when Pelf is “strong”, he can throw his four-seamer in the upper 90s, possibly as fast as 98 on occasion. So when that 90-MPH slider comes in, it acts as a change-up (8-10 MPH less is the ideal change of pace). Throwing that hard, Pelf can be the power pitcher he was in college, and simply overpower batters with his speed. The caveat is that the sinker may be thrown a bit faster — as it was on Friday night — and thus it loses its sink (Pelf was tossing the sinker around 93 on Friday).
So that still doesn’t explain why his record is so much better with extra rest, does it? Here’s my theory: when he’s strong, he feels good about himself and can pitch the game he’s most comfortable with: the power game. But when he doesn’t feel strong, he doesn’t believe he can dominate hitters on speed alone, and then the doubt sets in. Think about it … Pelfrey has been overpowering batters with his fastball since probably little league. Although he has a wicked sinker when it’s riding around 91-92, he’s neither confident nor comfortable — yet — in relying on it for consistent outs. It will take some time, but eventually he’ll feel comfy using his sinker as his “out” pitch. It will help immensely when/if he has a legit offspeed pitch to complement his sinker — and you may have noticed he attempted (but failed) in using a straight change to set up the sinker on Friday.
Until he develops that offspeed pitch, however, it will be rough go for Big Pelf. If he doesn’t feel like he can “reach back” and fire a 97-98-MPH heater past the batter, he won’t be 100% confident in retiring the batter.