We first encountered Joe Musgrove’s one-seam sinker around the All-Star break, when the Houston Astros right-hander was kind enough to show us the grip before his appearance in the Futures Game. I’d never seen a one-seam grip before, unless you count the one Zach Britton showed us. While we could spot glimpses of the sinker in the Futures Game and in his minor-league games, it wasn’t until Musgrove came up and started pitching in the big leagues that we could truly put his pitch in the context of other big-league sinkers. It’s weird.

Here’s that grip, again. It’s notable for a few reasons. It’s not a four-seam grip because he’s not pulling down on a seam to create the down-up spin that gives four-seam fastballs their trademark upwards “ride.” And it’s not a two-seam grip because he’s not pulling down on a seam with his middle finger, which traditionally creates the sideways spin that gives two-seam fastballs their sideways “fade.”



That one-seam sinker grip.

If you take away both of those movements, what are you left with? Downward movement without fade. And the pitcher admitted it back then when he said that he gets “more downward action than side to side” on his version of the sinker. Not too many pitchers throw this kind of pitch. In fact, it’s hard to find a comp for it at all.

First, you have to clean up the PITCHf/x for his fastballs, because the system is understandably a little confused by the movements on his pitches and has classified more than a few of his four-seamers as sinkers and vice versa. If you look at the heat maps for his movement and velocities, though, you can spot a pattern. Here’s how Musgrove’s corrected sinker looks against his PITCHf/x sinker and the league-average sinker from a right-hander. Still weird.

Joe Musgrove’s Weird Sinker Pitcher Pitch Start Speed Horizontal Vertical Spin Rate swSTR% GB% Joe Musgrove Sinker 91.5 -5.5 5.1 2271 10% 58% Joe Musgrove Corrected SI 90.5 -5.0 4.2 2230 13% 60% League Sinker/2Seam 92.2 -8.1 5.5 2059 5% 48% SOURCE: Statcast Movement in inches.

If you want to see where Musgrove’s sinker lives among his peers in a more visual format, check out the below. He’s got more sink than the pitchers with harder, flatter sinkers, and he’s got less fade than the guys with the plus, bendy sinkers.

Musgrove is over the top, and it’s sometimes rare for over-the-toppers even to have a sinker. Once you height-adjust release point and take the pitchers who throw in the top 20% by height-adjusted release point, his pitch gets a little stranger even. Only Luke Gregerson, Tyson Ross, and Blake Treinen throw from a similar arm slot and get as much sink on their sinkers. And while Treinen has a weird grip of his own, he and Ross have a lot more fade on their pitches.

Here’s a look at what we’re talking about.

That particular example of the pitch works well because, while it’d be risky to throw a normal sinker that far inside to a righty, this one doesn’t have that sideways spin and movement that reads like a sinker. So maybe Beltre thinks it’s a four-seamer… and swings over the top of the pitch. Here’s a spot where Musgrove can use his lack of fade to his advantage.

Given the lack of arm-side fade, you might be tempted to call this pitch a slider or cutter thing, but then it would only be a weird version of those pitch types. And while it’s tempting to consider this weird pitch bad because it doesn’t look like the pitches we normally call sinkers, there’s too much to be gained from being different in baseball. Weird is good, say Brad Ziegler‘s release point, Koji Uehara‘s splitter usage, Justin Verlander‘s fastball spin rate, Darren O’Day‘s Submarine Riseball, Clayton Kershaw‘s straight/cut fastball, Felix Hernandez’s power change, and a teenage Eno Sarris softly to himself.

For a guy who throws over the top, Musgrove has no problems getting horizontal movement like many of his fellow topsiders. The movement on his slider in particular — it has more cut than all save six sliders in baseball, and five of those are thrown by pitchers with much lower arm slots, like Justin Masterson, Joe Smith, and Chaz Roe.

Another weird pitch! Just more to watch for tonight when Musgrove takes the bump.