Buy Stock in Cubs Reliever Ryan Rolison While You Still Can

When Brad Keller toed the rubber for the Cubs last spring and started touching 98 miles per hour with his fastball, I didn't believe it. Hot radar guns aren't much of a problem in the modern game; Statcast is much less vulnerable to either error or manipulation than old-fashioned stadium or broadcast readings. Still, it was hard to buy into that level of heat from Keller, who had been a sturdy but not especially hard-throwing starter until moving into long relief the previous summer.

As it turned out, though, Keller's newfound Howitzer was for real. He had averaged 93.8 miles per hour on his four-seamer in 2024; that number shot up to 97.2 MPH in 2025. More intense stuff fueled his breakout as the team's first-half relief ace. He was the exemplar in the latest round of minor developmental miracle-making from the Cubs in the bullpen.

On Monday, we might have gotten another glimpse of that magic. Lefty reliever Ryan Rolison was a waiver claim this winter, after pitching in the majors for the first time at age 27 in 2025. Arguably, he only got as much time as he did (31 appearances and 42 1/3 innings) because he had the good fortune to land on one of the worst pitching teams of all time: the 2025 Rockies. Even if you take some of the air out of his 7.02 ERA because he was pitching in mop-up duty at Coors Field (in front of a lousy defense), he doesn't exactly look like a big-league arm.

That version of Rolison averaged just 92.9 MPH with his four-seam fastball, which has the cut-ride shape the Cubs love. His fastest heater in the majors hummed in at 94.8. Monday's version of him is a different beast. Rolison threw just four fastballs in his outing against the Royals, as he recorded his three outs on just eight total pitches. Here are the velocities of those four heaters, though:

• 96.3 MPH
• 95.7
• 95.7
• 95.2

If Rolison is a guy who sits 95 and touches higher from his high three-quarter left-handed slot, he's a very valuable, flexible piece of the team's bullpen depth chart. His two distinct breaking pitches play nicely off that heat, and he has a useful changeup, so he can even neutralize right-handed batters. The Cubs don't really need him, if everyone is healthy when they break camp next month, but unlike Keller, they also don't have to stuff him onto the roster in order to keep him. Rolison has a remaining year of being optionable, so they could stash him in Triple-A if Caleb Thielbar and Hoby Milner are both healthy.

That said, a harder-throwing Rolison could be a strong third southpaw for the pen, even if the team is at full strength. He offers some of the things the team lost when they allowed Drew Pomeranz to walk via free agency, with a high-rise heater and good depth on his curveball. When the team claimed him, he appeared to be a simple scoop off the wire, based solely on the ability to shuttle him to the minors at a moment's notice. Now, it's possible to see real upside here. Rolison just might blossom into a high-leverage weapon in a playoff-aspiring bullpen. He's made the adjustments needed to tap into a new vein of electricity in his arm, and if he can show enough command, he might deliver enormous bang for the few bucks the team forked over to bring him in.