After In-Season Pitch Mix Overhaul, Ryan Rolison is a Whole New Dude

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He didn't have the luxury of the inning being over, so when Ryan Rolison knew his own assignment was complete Tuesday night, he had to confine himself to roaring triumphantly into his glove and stomping back to the grass behind the mound. That's a bit less satisfying than going all the way to the dugout that way and having the fans at the same fever pitch as you, but it'll do. Rolison faced five batters bridging the ninth and 10th innings of Chicago's 8-2 loss to the Miami, shutting things down after coming in with one out in the ninth and fanning both hitters he saw with the Manfred Man in place in extras. It was a heroic effort.

All year, Rolison has been an under-the-radar hero in this bullpen. Stepping into the role filled by Drew Pomeranz in 2025, he's been eerily similar to Pomeranz in effectiveness. Pomeranz had a better ERA (2.17) than Rolison's (2.90) and he missed more bats, but Rolison has a higher Win Probability Added (WPA), at 0.92, than Pomeranz had (0.65). He's also pitched more for the team than Pomeranz did for last year's.

Part of the story of Rolison's success is that his fastballs are averaging 95 miles per hour, up a full two ticks from his 2025 heat. His arm angle is up a little bit, and he's getting more carry on his four-seamer, though some of that is just that he no longer pitches half his games in Colorado. As important as the '95' in that first sentence of the paragraph, though, is the 's' after 'fastball'. That's new—and it's not the only new thing going on in his arsenal, either.

Last season with the Rockies, Rolison was a fastball-curveball guy, with a four-seam heater that cut but didn't ride much. (Really, it was as much a cutter as a four-seamer.) It was a very north-south look. Even his slider was just a shorter, tighter version of that curve.

That approach produced miserable results, though again, Rolison was pitching in Colorado. Bad things happen to pitchers there, and even worse things happened before this year, when a more competent front office came in to run things. Rolison wasn't in a good environment in which to succeed, and he wasn't getting good advice. When the Cubs acquired him, they immediately got him throwing harder. They also got him back to using a wider mix of pitches, hearkening to his time as a starting pitching prospect.

The transformation wasn't complete when the season began, though. There were things the Cubs asked Rolison to try even in Arizona that didn't fully take root until the middle of this season, and one that's only becoming real now, in the final days of the regular campaign. Let's take a tour of the changes.

Rolison Introduces a Sweeper—Then Goes Wild With It

Last year, Rolison leaned mostly on his curveball as a secondary offering, especially to righties. Against lefties, he used his slider more, but the slider was little more than an abbreviation of the curve: same spin profile, same movement direction off the fastball, just faster and shorter. That's still, basically, true.

However, the slider isn't really the breaking ball worth talking about anymore. As the season has progressed, Rolison has leaned more and more on a new sweeper, at the expense of the traditional slider. Here's his month-by-month pitch usage against lefty batters:

The slider was his main breaking ball against same-handed hitters as recently as May. It's now a memory. The sweeper has come in, and it's a much more effective pitch, missing bats at roughly twice the rate its predecessor did. As you can see, though, it's not the only major recent change.

He's a Sinker Guy Now

Mid-stream, after trying but failing to find a usage pattern and a set of locations where his cutting four-seamer could avoid barrels sufficiently, Rolison has changed tack. He's still very much a natural supinator, but he and the Cubs have found a sinker that works for him. Above, you can see the way his usage of that pitch has obviated his four-seamer against lefties; that's somewhat common among lefty relievers. More surprisingly, the sinker is also stealing the four-seamer's fastball share against righties:

Rolison works from a much higher arm slot than most sinkerballers will, but that's not unusual for the Cubs. The same is true of recent acquisitions David Peterson and Clay Holmes. Unlike those two, Rolison doesn't have much heavy action on the sinker; it's better described as a running two-seamer. But that just makes him kin to Ben Brown, who tapped into that same pitch with great success before getting hurt earlier this year.

Suddenly, there's a whole lot more east-west to Rolison's pitch mix. He can attack both sides of the plate, and as he gets more comfortable commanding that supinator's sinker, he's also able to fool batters exceptionally well based on his spin and the resulting movement—which doesn't correlate all that closely to the spin direction out of his hand. Rolison has become an unlikely master of seam-shifted wake, with the sinker and sweeper, in particular, taking off to the arm and glove side (respectively) in ways the hitter can't anticipate by reading the spin axis.

That hasn't turned him into a true relief ace. Rolison still doesn't miss many bats—especially against righties. The curve remains his best breaking ball against those hitters, and it didn't get the same velocity bump as his fastball this year. That's made it a bit easier to spot and hold off on, for batters, than it would be if it were a bit firmer. See the way he's started mixing in his sweeper even to righties, lately? That's because the sweeper, at 85 MPH, is every bit as hard as his shorter slider was last season. When he can set it up and locate it well (down and in, preferably breaking just out of the zone in the direction of the back foot), that pitch can work even to opposite-handed batters. It might eventually usurp the curve.

For now, though, no more changes are needed. Rolison's new approach has him inducing more weak contact, and when Craig Counsell can deploy him according to plan, he has swing-and-miss stuff, too. He came up huge Tuesday night, even if his teammates didn't. It's been a breakout year for the southpaw, and he's become the unquestioned No. 1 lefty in Counsell's bullpen for October. It's a whole different pitch mix than he had a few months ago, which makes him a whole different pitcher. He might even be a good enough one to make a difference for a pitching-starved team come next week.