The Ultimate Roogy

With the advent of Pitch F/x and the dissemination of velocity and pitch type data into the public over the last few years, and now leading to stuff like the linear weight values we have for specific pitches on the site here, it’s becoming easier and easier to figure out why some pitchers are successful and others are not. We’re able to quantify things that we’ve never been able to get a handle on before, and the analysis that’s being done with pitch data right now is tremendous.

However, even with all those advances, there’s still one glaring question that I don’t know that anyone has the answer to – how the hell is Mark DiFelice getting people out?

You probably have seen DiFelice at some point now that he’s thrown 45 innings as a major leaguer over the last two season and pitched for Italy in the World Baseball Classic this spring, where he threw four shutout innings against Venezuela. That wasn’t his only taste of success – since coming to the big leagues, he’s posted a 1.81 BB/9 and a 9.07 K/9, which have led to a sparkly 2.01 ERA. He’s been one of the reasons the Brewers bullpen has been holding leads all year.

But how he does it is beyond me. Here’s a Pitch F/x chart of what he throws in a normal game.


There’s 29 blobs in there representing pitches from DiFelice in that specific game (May 10th versus the Cubs). Pitch F/x labeled most of them sliders, while it called a few others change-ups, but in reality, it’s just a cut fastball thrown so slowly that the algorithm doesn’t recognize it as such. If you want to see the pitch, there’s a .gif over at Driveline Mechanics.

That’s his arsenal. An 80-84 MPH cut fastball. That’s it. He throws that pitch, and that pitch only, 99% of the time. He also has thrown this loopy 72 MPH curveball a couple of times this year, but practically every pitch he throws, in every game, is this low-80s fastball with some tailing action away from right-handers. I faced guys in high school who had better stuff than this.

However, whatever DiFelice does to his cut fastball, or however he hides the ball, or whatever voodoo spell he chants before he pitches, it works wonders against right-handed bats. Here’s his career splits since joining Milwaukee:

Vs RHB: .149/.192/.202, 120 PA
Vs LHB: .321/.357/.717, 56 PA

Opposing right-handers have a .393 OPS against DiFelice. Opposing left-handers have a 1.074 OPS against him. He basically turns every RH bat he faces into a pitcher, and every left-handed bat into Albert Pujols. This is the most ridiculous platoon split I have ever seen. Yes, it’s a small sample size, but given what DiFelice throws, we’d expect left handed major league batters to use him as batting practice, so that part is likely not an anomaly.

Can he really keep pitching like the best pitcher ever against right-handed bats while throwing one pitch in the low-80s, though? Everything I’ve ever been taught about baseball says no, but at this point, we’re on our second year of him embarrassing high quality bats, and I can’t come up with any reasons why he can’t keep doing this. Perhaps the real question shouldn’t be “how is Difelice getting people out”, but instead “why aren’t the Brewers forcing every pitcher they have to learn how to throw that thing?”

Dave is the Managing Editor of FanGraphs.

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13 years ago

Makes me wonder – what does his pitching motion look like? Deceptive delivery or something? That explanation usually gets overplayed by broadcasters, but with that chart, is there any other way to explain his success? I’d think that if a hitter knows which pitch is coming, the velocity with which it will arrive, and the basic movement pattern, it should turn both handed hitters into Pujols.

I looked for a video but had no luck.

13 years ago
Reply to  Dorsey

Look at the .gif.

13 years ago
Reply to  JLP


13 years ago
Reply to  JLP

Oh. If that was there the whole time, I need to stop drinking at work.