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Spin Rate, Curveballs, and Why Carl Edwards Jr. and Mike Montgomery Are Exciting

Analysis and Commentary

mike montgomery cubsOne of the big “things” sabermetrically-inclined people will be discussing next year is spin rate.

At its simplest, spin rate is literally the revolutions on a baseball as it comes toward home plate. It has come up a bit already in talk around the baseball world – for example, late in the year we discussed how Carl Edwards Jr. has elite spin rate. But the data really hasn’t been all that available to third parties for analysis, so the discussion has usually been a stray article here and there. To be sure, and as far as I know, the data is still not entirely freely available to everyone, but the discussion of it is becoming more and more prevalent, and I’m predicting (hoping?) we see a ton about it in 2017.


Spin rate, when analyzed in conjunction with the type of pitch, can tell us quite a bit. For example, a huge spin rate on a four-seam fastball (like Edwards has (plus his cuts)) allows the ball not to drop as much as you’d expect (“rising fastball”), which can make it very difficult to square up. Ever wonder why one guy’s 90mph fastball seems to have more life than another guy’s 92mph fastball? It’s possible what you are unconsciously noticing is the hitter’s reaction to the pitch, not the pitch itself – and that could be a signal that you’re seeing a huge spin rate. (Or possibly good extension by the pitcher, making the pitch reach the catcher slightly faster than the pitch speed otherwise indicates. Surprise: Edwards gets good extension, too. Yes, he’s really good.)

OK, so all of that was the nerdy preamble to sharing this article by Mike Petriello, a writer for who regularly gets into this stuff.

Petriello wrote a fantastic piece on the return of the curveball, whose usage saw a huge spike this past season, and saw spin rate gains across the league. As you might suspect, when it comes to the curveball, a higher spin rate generally means more movement. And, once again as you might suspect, more movement generally means more batter whiffs and less hard contact. Read Petriello’s piece for the full analysis.

So, then, if you’re a dude who can throw a curveball with a huge spin rate, that’s probably going to be a very good pitch.


And guess who added RPMs to his curveball after a midseason trade and started throwing it a ton more? Yup, that’d be Cubs lefty Mike Montgomery. When we talk about hoping the Cubs and pitching coach Chris Bosio can take a guy and improve him after an acquisition, this is what that looks like. From the outside, it appears that the Cubs isolated a pitch that Montgomery could improve, AND had him use it more often.

If Montgomery can sustain his curveball usage (it was near 30% with the Cubs, after being closer to 10% before the trade) and continue to command the pitch, it’s not unreasonable to project that his performance with the Cubs (particularly as he became a starting option and then one of the most trusted relievers in the bullpen) could continue into 2017.

Indeed, the possibility that he succeeds as a starter with the Cubs feels much more strong after considering this analysis than it did before, especially when you factor in that he’s far from a one trick pony: although the curveball might now be Montgomery’s best pitch, he also has a positive value cutter/slider and a positive value changeup. Only his fastball was a negative value pitch, but if he can continue to command the other three, he’ll need to lean on the fastball less and less. (And, it’s not inconceivable that, the more he uses the curveball, the better the fastball will be, relatively speaking.)

And just to bring things back to spin rate and Carl Edwards Jr. so that we can button this up neatly? Yes, he has an above-average spin rate on his nasty curveball.



Brett Taylor

Brett Taylor is the Editor of Bleacher Nation, and you can find him on Twitter at @BleacherNation.