Sweepier By the Day, Ryan Rolison is Becoming the Linchpin of Cubs' Fragile Pitching Carriage

Over halfway through the season, the regression monster hasn't yet caught up to Ryan Rolison. In fact, with Caleb Thielbar finally, sadly looking his age and Hoby Milner sidelined by an emergency appendectomy, there's not much doubt that Rolison is now the Cubs' top left-handed reliever. It's less fun to note this part, but with Daniel Palencia headlining tim times and  a long list of injured righties, Rolison might even be their relief ace, without regard to handedness. The only other candidate is Jacob Webb, and if anything, Rolison has been more consistent.

That's not to oversell him. Rolison's win probability added (WPA) over the 25 appearances since he came to the majors to stay in late April is -0.16. He hasn't been dominant, and he doesn't even have a save. His ERA is great, but his peripheral numbers are more like "good". He's allowed a pretty average 6 of 17 inherited runners to score. He's arguably the team's relief ace right now, not because he's great, but because the team is so far underwater in the bullpen.

Still, this level of contribution is vital, especially for a team so awash in injuries and underperformance. Rolison started the season with Triple-A Iowa, even after a good spring. The Cubs picked him up over the winter, in no small part, because he's an optionable arm. He first came up on April 14, the first time the team was in scramble mode in the relief corps, but he stayed just that one day. He didn't come back until April 24. Since then, though, he's appeared 25 times and pitched 30 2/3 innings in the Cubs' 59 team games. Over a full season at this pace, he'd work 69 times and amass just under 85 innings. Craig Counsell has often been short on hurlers who are so much as available, let alone reliable; Rolison has been a rubber arm who doesn't give away games. 

He's markedly better than he was last season. Made to look much worse than he was by playing his home games in Colorado, Rolison had a 7.02 ERA in 2025, with little life on his fastball. He's up about 1.5 miles per hour on the four-seamer this year, with a more aggressive delivery in which he gets down the mound farther and draws more force from his landing leg. But more importantly, he's increased the induced vertical break on that heater by 3 inches, mostly because he's no longer pitching in the mountains. His curveball has more depth, too.

To all of that, he's added a sweeper. The Cubs started talking to Rolison about incorporating that pitch back in the spring, but only stepwise as the season has progressed has he worked it into his attack within games. 

It's still his fourth-most used offering, but between that sweeper and the sinker that he's also mixed in more often of late, Rolison is moving east and west more than he has in the past. The variety of shapes he's now showing hitters is as wide as that of many starters, and because he's not seeing right-handed batters two or three times in a game, he can more than get by without a reliable changeup. It helps, of course, that it turns out that his new sweeper is the best swing-and-miss weapon in his arsenal.

Tweak by tweak and sweeper by sweeper, Rolison has worked his way to striking out over a quarter of the batters he faces. He still walks too many opponents, but he can get off their barrels well with the two fastball looks, and his three breakers ensure that he gets the whiffs he needs. He's still not a playoff-caliber relief ace, but he's cemented himself as this year's Drew Pomeranz or Tyson Miller: a fine middle reliever who can be a bit more in a pinch, for a team very much in that kind of pinch.