Who Could Drop Their Arm Slot for More Success?

Yesterday, we identified Jeremy Jeffress as a pitcher who benefited greatly from dropping his arm slot, adding more sink and fade to his two-seamer. The idea was that his four-seamer was straight and possessed below-average spin, so moving from that pitch to a sinker, while dropping the slot, gave him a better foundational fastball. There’s a roadmap there. Let’s follow it.

Jeffress had below-average spin for his velocity, had a flat and straight four-seamer, featured a fairly over-the-top delivery, and used the four-seamer much more than the sinker. By indexing spin on four-seamers and then sorting the more common fastballs by height-adjusted release point, we can produce a list of over-the-top four-seam pitchers who might benefit from dropping down like Jeffress.

Here’s the list, sorted by release point. A negative release point here means the pitcher releases the pitch that many inches above his listed height.

Gibson used to have a decent sinker by movement, and then last year he inexplicably raised his release point and lost a ton of movement on the pitch. I’d guess that his slot change was designed to get more drop on his curve — which, objective attained — but at the cost of his fastball. Probably best to undo that decision, considering that last year was his worst by any metric.

Ride — the lack of drop that great four-seamers exhibit — is usually a function of spin and arm slot. So some of these over-the-toppers have harvested the most ride they could get from their spin and probably don’t require any alterations. Ryan Garton, Alex Colome, and Michael Wacha all get more than an inch of ride, and that’s useful for setting up their breaking pitches and getting whiffs on its own.

Justin Nicolino is already a sinkerballer… and gets good movement on the pitch, though not great sink. He was an inch-plus worse than average on sink. Maybe he should consider lowering his slot a little. Derek Law’s situation is complicated a little by injury — perhaps this is the best thing for his arm.

But now we’ve gotten to the best fit on the list, maybe. Before moving to the White Sox in the Adam Eaton trade, right-hander Reynaldo Lopez was hit hard in his debut with the Nationals. His four-seam was straight, with no ride and 7% less spin than the average plus-velocity four-seamer. His changeup lacks sink. Dropping down would likely address both of those concerns. Here’s his four-seam:

The matter is complicated by the fact that we don’t know what his sinker would look right now because he didn’t throw one, reportedly. There’s one way to estimate it, though. To do that, I looked at the 35 right-handed pitchers (a) whose four-seamer most resembled Lopez’s and (b) who also threw a two-seamer. Those 35 righties averaged 5.5 inches of fade and average vertical movement on their four-seamers. As for Lopez, he averaged 5.8 inches of fade and average vertical movement. So the comparisons are reasonable.

Those 35 pitchers give us an idea about what Lopez’s two-seamer would have looked like, if he’d thrown one. In this case, it would have been average in terms of horizontal movement but possessed more than two fewer inches of drop than the average two-seamer. Hello, arm-slot change.

I once attempted to define expected movement based on arm slot in order to put a number on deception, and that attempt created an equation that related arm slot to vertical movement. The results suggest that, roughly speaking, every four inches of change in vertical release point provides a little bit more than an inch of drop. Using that ration, we can hypothesize that Lopez would have to drop down eight inches to create the average two-seamer by movement.

That’s a bit extreme. The biggest two drops last year — James Pazos and James Paxton — didn’t alter their slot by more than 6.6 inches. Maybe it’s too much to ask.

But it’s interesting that Lopez is within reach of an average two-seamer by movement. He averaged nearly 96 mph on his two-seamer last year, and even a move to starting full time and age should leave him with a two-seamer over 94 next year. Last year, only seven starters threw a two-seamer that averaged 94-plus mph and had at least average drop: Carlos Carrasco, Robert Gsellman, Carlos Martinez, Jimmy Nelson, Luis Perdomo, Jeff Samardzija, and Jameson Taillon. That’s a decent group.

Maybe it would work. Even with a four-seamer that exhibited almost exactly average movement and below-average spin, Reynaldo Lopez was about league average when judged by strikeouts, walks, and homers. That, despite two good secondary pitches that got a whiff once nearly every five pitches. Maybe he should drop down for more movement.

The key is repeatability and comfort. James Paxton could make that big of a change because it finally felt right, because it was his natural throwing motion. Jeremy Jeffress reported no problems making the change. If Lopez can’t repeat from the new slot, or feel comfortable, he shouldn’t do it, of course. But if it feels okay? Fire away.