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Not The Weekly Mailbag: Is a Cutter a Fastball?


Mariano Rivera has a pretty clear opinion about whether or not a cutter is a fastball. Photo Courtesy of Ron Vesely, Getty Images.
Shortly after Major League Baseball (and most of life as we know it) was shut down in mid-March, Pedro Moura wrote a fascinating piece over at the Athletic discussing prevailing opinions on whether a cutter is a type of fastball or off-speed pitch. A subscription to the Athletic is required, but I highly recommend reading it. As someone who has pitched, and thrown the cutter extensively, I found it fascinating to read about how differently elite pitchers think about the pitch. Two of the most prominent throwers of the cutter in today’s game, Walker Buehler and Kenley Jansen, view the pitch very differently. Of greater importance to Yankee fans though, is that the person who most famously utilized the cutter as his primary (nearly only) weapon: Mariano Rivera.
To no one’s surprise, Mo thinks about the cutter as a fastball. In the article, Mo even goes further by saying that most of the people who believe they are throwing cutters are actually throwing sliders. The implication is clearly that Mo thinks that people who think of a cutter as an off-speed pitch are really throwing some variation of a slider. Mo, the greatest reliever in the history of the game and the man credited with having the best cutter in the history of baseball, is a hard man to argue with. This article has caused me to contend with my own thoughts on the pitch. Having never closely examined the philosophy of throwing a cutter, I had really never come to any hard and fast conclusions, but once I examined the use of the pitch, the results surprised me.
Prior to thinking a little more deeply about it, my knee-jerk opinion was identical to that of the great Mariano Rivera: a cutter is a fastball. I use two different grips for the pitch, seen below:
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Two-Seam, Top-of-the-Horseshoe Cutter Grip
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Offset Four-Seam Cutter Grip
The first of the two grips shown above allows the pitch to show a little late sinking action in addition to cutting hard at the back-end of its flight. The second grip (when the pitch is executed correctly, anyway) causes the pitch to come in like a four-seam fastball prior to cutting in it’s last five feet of flight. Thrown correctly, both of these pitches are executed and move like fastballs.
However, the depth and velocity of the pitch using either grip can be altered with ease, and it completely changes the intent of the pitch. Here is a side view of my hand when throwing this pitch:
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Tucked Grip
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Untucked Grip
In the first grip, the ball is more tucked towards the palm. Using the two-seam cutter grip, the velocity gap between a four-seam and cutter widens, and the cutter shows more depth and cut, but still bears some similarity to the fastball. Using the four-seam cutter grip with the ball is more tucked towards the palm, the pitch has late dive and more severe cut.
In the second, “untucked” grip, both the two-seam and four-seam grips shown previously behave as I initially stated: late-break, and similar velocity to the four-seam fastball.
I am not a Major League pitcher, but I used four different grip combinations for one pitch that I called a “cutter”. Sometimes, it looked like a fastball, sometimes it looked like a short slider or a change-up with cut.
At the end of the day, Mariano Rivera is probably right. After all, as Yankee fans, we all learned to trust Mo when it came to throwing a cutter. A true cutter is probably a fastball. However, I and many other pitchers in all likelihood, believe that the issue comes down to intent. If you throw the cutter with fastball-like intentions, it’s a fastball. If you throw it with the intention of an off-speed pitch, it’s an off-speed pitch. This is likely why pitch tracking systems have trouble distinguishing cutters from sliders and even splitters in some cases: a cutter is all about intent to a pitcher, and no one can agree.