Robbie Erlin, Tommy Hottovy, and Marcus Stroman Expound on Curveballs

Pitchers learn and develop different pitches, and they do so at varying stages of their lives. It might be a curveball in high school, a cutter in college, or a changeup in A-ball. Sometimes the addition or refinement is a natural progression — graduating from Pitching 101 to advanced course work — and often it’s a matter of necessity. In order to get hitters out as the quality of competition improves, a pitcher needs to optimize his repertoire.

In this installment of the series, we’ll hear from three pitchers — Robbie Erlin, Tommy Hottovy, and Marcus Stroman — on how they learned and developed their curveballs.


Robbie Erlin, San Diego Padres

“I started throwing my curve when I was nine. Everybody frowns upon that — throwing one that young — but I never had any problems. Basically, my dad put me on one knee and taught me. It was almost like casting a fishing reel. What that does is… when you throw a curveball, you want your elbow to come up a little bit. If your elbow is coming down to throw the curveball, you get exposed. That’s when it’s dangerous [health-wise].

“My dad pitched in high school — he was a righty — and he told me that’s how he was taught. So yeah, he put me on his knee and said, ‘Just flip it to me. Just work on spin. We’re not throwing it hard.’ Eventually I got the feel of it. I started throwing it in games — flipping it out in games — but only once in awhile. Not too much as a kid.

“It’s the same grip today, and the same thought. I obviously manipulate it a little bit more — I accelerate a little more at times — but for the most part I’m still spinning the ball. I’m still getting extension. I guess the difference from when I first learned is that I’m driving the pitch to the target, as opposed to just flipping it in there and hoping it lands. I’m aggressive with it.”

Tommy Hottovy, Chicago Cubs [pitching coach]

“Growing up, I was one of those guys that could naturally spin a baseball. I was a decent quarterback, too. The throwing motions [for a baseball and a football] are similar in how you’re imparting spin. Some guys have better feel staying behind the baseball with two fingers, and feeling it off the tips of their fingers, versus a breaking ball where you come around it and it’s kind of spinning off the sides of your fingers. A football is more like that motion, like a breaking-ball motion.

“Some pitchers… a guy like Yu Darvish could wake up in the morning and spin a slider with ease. Some guys just have that natural ability to spin a breaking ball. I was just lucky to be one of them. Of course, I didn’t have the really good fastball. I had movement, but not a ton of velo. What I mostly had was [the curveball].

“I learned how to throw it early. Honestly, I learned it earlier than kids should learn one. I was nine or 10 years old, spinning a true 12-6 curveball. It wasn’t very hard, but again, I could spin it. The way I would practice was to take a five-gallon bucket, and try to drop [the ball] in the bucket. That was from probably 35-45 feet away. Then you… it’s like shooting a free throw. You kind of start close, you feel the spin, and then you back up. That’s kind of the way I learned how to spin a baseball, how to throw a curveball.

“I never changed the way I threw it, but I did change the grip a few years into college. I had good break to it, but not the velocity I wanted, so I went to more of a four-seam grip to get more seams working for me. Once I did that, the velo went up. I’d been throwing it with kind of a two-seam grip — that’s what felt comfortable — but once I realized how the four seams would work for me, I changed.

“There are a ton of different grips, or placements on the ball. There is the spiked curveball, which is the [pointer] finger up. There is the curveball where you have both fingers on the ball. There are curveballs like the one Mike Montgomery throws. His pointer finger is basically up — it’s not on the baseball at all — so he’s imparting spin with two fingers: his middle, and his thumb.

“You can alter your thumb placement. Some guys like the thumb low, so that the ball pops out easier. Some guys like it higher, so it’s completely out of the way and you’re imparting more spin. It really depends on what you’re trying to accomplish. Do you want more of a lateral version of it, or more of a downward version of it? There are a lot of ways to play it, and as coaches we have all these resources now — the Edgertronic cameras and Rapsodo — to show guys what finger placement does on certain pitches.

“You want to find a release point where it comes out looking the same. Everybody thinks that if you throw a fastball from this slot, you need to throw a curveball from [the same] slot. But what if your curveball pops out from there? Maybe if you adjust that slot just a tick, it will come out cleaner. With the resources we have, we can help guys fine-tune what the ball looks like coming out of the hand.”

Marcus Stroman, Toronto Blue Jays

“Everyone is calling it a slider, but it’s my curveball. I throw it anywhere from 78 to 86 [mph]. I throw it harder, I throw it softer, but with the same grip. It’s really more of a slurve, but I consider it my curveball. It’s a pitch I’ve been throwing a lot lately, and getting swings and misses with. Basically, I have my grip and I’m throwing it aggressively in the zone. That’s pretty much my only thought process, to spin it as much as I can.

Marcus Stroman’s curveball grip.

“I do throw a slider, as well. And a cutter. So I throw all three. But the one that everyone has been talking about lately is the curveball. Like I said, it can be pretty much like a slider when I throw it harder, when it’s 84-86. Changing the velocity is about finger pressure and stride length. I can use my stride length to kill the ball speed.

“This is the same pitch I was throwing when we talked back in 2013. In 2014, as well. Then I kind of went away from it in ’15, ’16, ’17, and ’18. Now I’m throwing it again. It’s like the slurve that I threw a lot in college. It’s a pitch that feels comfortable in my hand.

“Like I said, I’m thinking curveball, but when I throw it effectively it’s not 12-6; it’s more slurvy. It has horizontal and vertical depth to it. I can manipulate the horizontal and vertical depth, depending on the count and what I want to do with it. I’m pretty good at manipulating this pitch.

“Why did I kind of stop throwing it for awhile? I’ve been through a lot of phases. I was a four-seamer, then I was a sinkerballer. Certain pitches pair better with certain pitches. As pitchers, we’re always adapting, always evolving, always changing things. I went away from it and had success. In 2017, I was going sinker, cutter, slider. Now I’m back to something that has bigger depth and more movement, to get more swings and misses.

“I’ve always done my own thing. No one taught me that pitch, nor told me to throw it. I’ve always manipulated the ball. I’ve always found grips, and found ways to get guys out on my own.”


The 2018 installments of this series can be found here.

David Laurila grew up in Michigan's Upper Peninsula and now writes about baseball from his home in Cambridge, Mass. He authored the Prospectus Q&A series at Baseball Prospectus from December 2006-May 2011 before being claimed off waivers by FanGraphs. He can be followed on Twitter @DavidLaurilaQA.

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