Adding Pirates RHP Mitch Keller Would Boost Cubs Rotation

As the MLB trade deadline looms, the Cubs find themselves in a precarious position: close enough to contend, but not quite there yet. With ace Justin Steele shut down for the season and the rotation pieced together on a weekly basis, the need for a proven arm has gone from optional to urgent.

Enter Mitch Keller.

The 28-year-old right-hander has emerged as one of the top arms to help stop the bleeding in the Cubs’ starting rotation. USA Today’s Bob Nightengale has reported on that interest more than once (here and here), writing that the Cubs “would love to get their hands on Keller” and that they have been in “serious talks” with the Pirates for over a week.

Keller signed a five-year, $77 million extension with Pittsburgh in 2023 that keeps him under team control through 2028, meaning he wouldn’t just be a rental. The Cubs are leaning heavily on a mix of young talent, mid-tier arms, and swingmen/openers as the rotation’s cracks have become glaring. The team is plagued by some major issues, which is where Keller comes in.

Without Steele, no starter at the back end of the rotation is consistently going six innings. That has torched the bullpen and exposed depth issues, especially when starting series with the Nos. 3-5 starters. Keller has averaged 6+ innings per start in 2025 and has thrown over 190 innings in back-to-back years. He’s shown to be a workhorse who can get out of jams to save bullpen arms.

This could lead to using bigger names like Drew Pomeranz, Porter Hodge, and Brad Keller more efficiently and less often, saving their arms for when they’re most needed.

On a related note, Keller’s career-best 6.1% walk rate and elite first-pitch strike percentage (~66%) make him one of the most efficient arms available. Though he doesn’t strike a lot of hitters out, his six-pitch mix — four seam, sweeper, slider, sinker, curveball, and changeup — helps hit to limit hard contact.

Mistake pitches allow opponents to either get back in the game or blow it wide open. Keller has given up just seven home runs this season, giving him a 0.63 HR/9 mark that is better than all but six qualified pitchers. That would be a big boost to a rotation that has allowed 76 homers, second only to the A’s (81), while sitting near the bottom with a 1.52 HR/9 tally.

There’s a temptation at the trade deadline to hunt for arms that will blow you away with ace-level dominance. Keller isn’t that. He’s not going to overpower hitters with 98 mph gas. He won’t headline a playoff rotation for a World Series contender. But he doesn’t have to. With the offense producing the second-most runs per game, the Cubs don’t need a lights-out ace — they need someone who can keep them in games, throw quality innings, and give the bullpen a breather every fifth day.

What Keller does bring is something the Cubs badly need: a reliable mid-rotation starter who can help stabilize a group that’s been shredded by injuries and inconsistency.

In 2025, Keller is giving you a .248 opponent batting average; a 45.7% ground ball rate; seven home runs and 21 walks in 417 plate appearances. Those aren’t ace numbers, but they’re undeniably better than what the Cubs have gotten from Ben Brown, Colin Rea, and a young Cade Horton. Keller is not flashy, he’s functional. And in a rotation full of questions, functional is a step forward.

Think of Keller as a high-end No. 3 starter, someone who keeps you in games, eats innings, and doesn’t unravel after a walk and a bloop single. His control is sharp, his pitch mix is mature, and he doesn’t beat himself. Adding him won’t make the Cubs favorites overnight or even define their deadline. But it may just be a move that adds a couple of important wins as the season winds down. That could be the difference between winning the division and battling for a Wild Card.

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