The Rise of the Cut Fastball


I learned about pitching fairly recently, since I was born in 1990. My impression of how pitching generally works, therefore, has largely been formed by what pitchers between 1997 and 2007 did.

What did those modern pitchers “generally” do, you ask?

Well, obviously, most pitchers worked off of four-seam fastballs, although a fair amount threw “sinkers” or two-seam fastballs as their primary pitch. Then, they also had some sort of a “breaking ball”—a slider, curve, or both. Then, they have an “offspeed pitch”—a changeup or, in rare cases, a splitter.

And then there’s the cutter, which Al Leiter and Mariano Rivera threw.

Those were my basic impressions of pitching growing up around the turn of the century, and they’re pretty true for that time period. For example, in 2004, about 64% of pitches thrown were fastballs. About 13% were sliders, 10% were changeups, and 9% were curveballs, leaving the remaining four or so percent to be divided between cutters, splitters, and knuckleballs.  [...]

Why do pitchers seemingly “have” to pitch like this? Well, it has to do with which pitches work against same-side batters and opposite-side batters.

As you probably already know, breaking pitches, particularly sliders, are very effective against same-side hitters.  A pitcher can basically throw the ball right at the hitter and watch it break over the inside corner, or start it down the middle and break it off the plate down and/or away for a swinging strike. However, it’s tough to find a place to throw sliders (and, to a lesser extent, curves) to opposite-side hitters; rather than get backed off the plate by a pitch that looks like it’s headed right at them, they can pick up the break almost at the instant the ball leaves the pitcher’s hand.

Therefore, to effectively combat opposite-side hitters, a pitcher needs a good changeup or splitter. Changeups and splitters tend to move away from opposite-side hitters, so good ones like Dallas Braden’s can almost act like a reverse breaking ball.

Fastballs tend to show a moderate platoon split somewhere in between. Four-seamers tend to work better against opposite-side hitters than two-seamers, however. Therefore, the classic “sinker-slider” pitcher is equipped with the two most lethal pitches to same-side hitters, but the two weakest to opposite-side batters. Pitchers of this type need to develop a strong changeup or splitter to be viable starting pitchers; those that don’t wind up as relievers.

That all makes sense enough, and there’s plenty of data to back up the necessity of those pitches. It would seem that after 125 years or so of pitching, everyone’s figured out what works best to be a complete pitcher.

But they haven’t.

There’s a growing trend in baseball. More and more pitchers are abandoning the traditional fastball/breaking ball/changeup model for something very different.

The cut fastball.

Over the past couple of years, a high number of pitchers have trashed the majority of their arsenals to focus on the cutter. A high number of them have met with spectacular results.

When talking about cutters, of course, you have to start with that of Yankees closer Mariano Rivera. Rivera has been one of the most dominant relief pitchers in baseball history, throwing a cut fastball and only a cut fastball. He’s the only pitcher currently in the major leagues with only one pitch—even knuckleballers like Tim Wakefield and Charlie Haeger toss in a four-seamer or breaking ball now and then.

How can Rivera get such spectacular results from one pitch?

I mentioned before what makes the sinker and the slider so effective to same-side hitters. A sinker has fastball velocity and is going to run down and in to them, jamming them and forcing them to pound the ball weakly into the ground. The slider, with its late movement, can change from a ball to a strike (over the inside corner) or a strike to a ball (down and/or away) at the last instant.

What’s great about the cutter is that it basically acts like a reverse two-seamer to opposite-side hitters, causing jammed popups and weak grounders. But at the same time, the glove-side movement on the pitch can also make it work like a slider to same-side hitters, either for an inside-corner strike looking or a bad swing on a pitch off the outside corner.

Therefore, the cutter can be effective when thrown inside to opposite-side batters and on either side of the plate to same-side batters. So Rivera can just jam lefties and flummox righties without having to worry about a pitch specifically designed to combat either one.

For years, of course, we’ve looked at Rivera as a bizarre anomaly of sorts rather than a potential model for a new way of pitching. Only recently have other pitchers begun to take a similar approach.

We all know Oakland closer Andrew Bailey as the 2009 AL Rookie of the Year, and one of the most dominant relievers in the game. But in mid-2008, Bailey was a floundering starter at Double-A Midland, a C-grade prospect with a good curve and little else.

Around the All-Star Break of 2008, the A’s removed Bailey from the Midland rotation and stuck him in the bullpen, but they also made a significant change to his repertoire.

Gil Patterson, Oakland’s minor league pitching coordinator, has long been a proponent of the cutter. He worked with Bailey extensively upon the righty’s transition to relief, and they scrapped the two-seamer he used as a starter and replaced it with a cutter.

Bailey posted a sub-1.00 ERA the rest of the way, tore up spring training in 2009, made the A’s bullpen as an extra arm…and the rest is history. Throwing the low-90’s cutter gave Bailey an effective weapon to set up his big curveball, and the cutter actually proved more effective than the curve.

When Texas’ Scott Feldman came up to the majors, he was a sidearmer with a sinker and a slider. Before the 2008 season, however, the Rangers did a complete overhaul of Feldman, preparing him for a move from relief work to the rotation.

They raised Feldman’s arm angle up to a standard three-quarters slot and took the sinker and slider all but out of his repertoire, replacing them with a cutter and curve (and the occasional changeup). Feldman showed good signs in 2008 of being a solid pitcher, but shied away from overusing the cutter, preferring a traditional four-seamer instead. However, he found the cutter was getting better results, and leaned more heavily on the pitch in 2009.

According to Fangraphs’ Pitch Type Linear Weights, it was arguably the most effective fastball (four-seam, two-seam, or cutter) in baseball last season, at 2.56 runs above average per 100 pitches. That means that for every 39 cutters Feldman threw, the opposing team scored one run fewer than they would against 39 average pitches.

That’s pretty staggering stuff.

More and more pitchers are following this lead. Dan Haren, Jon Lester, Roy Halladay, Josh Beckett, Ricky Romero, Dallas Braden, Phil Hughes, John Danks, Kevin Correia, Jon Garland, and Justin Duchscherer are just some of the pitchers who didn’t throw a cutter just a few years ago and have cut large parts of their arsenal (especially sliders and other fastballs) out of their repertoire in favor of the cutter in the last couple of seasons. And if you’re wondering why Indians righty Mitch Talbot is finding so much early success…he’s got a good cutter.

Use of the pitch league-wide is now up to the 6-10% range, about three times as high as it was in 2007. Given all the advantages the pitch presents, it’s likely that number will continue to rise as more and more struggling pitchers, like Bailey and Feldman, turn to the cutter to give them a new weapon.

Who knows where this might lead in ten or twenty years? Perhaps sliders will be like splitters or knuckleballs—a “specialty” pitch only a select few throw. The cutter, being essentially just a fastball, causes far less arm strain than a slider, so if it proves more effective over the long haul, the adoption of the cutter could also alter the injury landscape for pitchers.

The change is happening right now. It’s exciting to see where this trend takes pitching in the modern era.

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Tags: Andrew Bailey Mariano Rivera Mitch Talbot Scott Feldman