After David Peterson Trade, What Other Trade Candidates Make Sense for Cubs Rotation?

[Paul Niemiec]

Image courtesy of © Rick Osentoski-Imagn Images

Last week, the Chicago Cubs made an early (but necessary) trade to address their pitching depth, acquiring left-handed starter David Peterson from the Mets. Peterson, the longest-tenured Met before he was dealt, is not having the year he would have hoped. He had been shuffled between the rotation and bullpen, making eight starts in 16 appearances, “good” for a 6.09 ERA, but with a more encouraging FIP of 3.85. At this point, the Cubs can’t be too picky about who they use to start games, with both Edward Cabrera and Ben Brown hitting the IL for the foreseeable future. They do seem to have had reasons to like Peterson, but he was an emergency addition.

With the return of Matthew Boyd, the rotation should include Boyd, Shota Imanaga, Peterson, Colin Rea, and Javier Assad until Jameson Taillon returns. Peterson should fare better with the Cubs’ defense, as he has been a heavy groundball pitcher throughout his career. In his first start, he inspired confidence against the Brewers on the road, pitching 5 2/3 innings while allowing only two earned runs. 

The Cubs sent 2024 second-round pick Cole Mathis, a third baseman from the College of Charleston, back to the Mets in a one-for-one trade. He was a very low-grade prospect, even in a Cubs system not exactly overflowing with talent; they bought low on Peterson to bolster their rotation depth.

That's probably the type of deal we can expect to see the Cubs make again before the trade deadline on August 3. Depending on where they sit in a month, we may see them make a legitimate swing at a big name, while dangling prospects like Jefferson Rojas, Pedro Ramírez, Ethan Conrad, and others who sit amongst their top prospects. For now, though, the strategy of moving lesser prospects for pitching depth is necessary for them to stay afloat. Whether you agree or not, the window is open now for this team to be competitive, so unless there is another crumbling over the next month (and maybe even if there is), they will be buyers.    

Whom might they move, in that scenario? Ramírez and Rojas are two of their top guys, so barring a blockbuster trade, they will stick around, even if it takes creativity to get them into the lineup in the near future. Eighth-ranked prospect Jonathon Long, No. 9 James Triantos, No. 14 14 Angel Cepeda and No. 17 Ty Southisene are all guys you could see get moved in a trade similar to the Peterson-for-Mathis swap. Frankly, with the team in go-for-it mode, none of their prospects should be considered “untouchable”, but these mid-range guys with no clear path to the show should be an afterthought if it means putting the Cubs in a better position for 2026. 

In the spirit of the Peterson trade, let's come up with a potential trade target for each of the players mentioned above. The criteria will be starters who are struggling, but also on teams playing poor defense. Each of these players should be able to turn a corner with the Cubs. Certainly, Jed Hoyer won’t be able to pull off a one-for-one trade for all of these guys, and they could be packaged for a bigger name instead, but it's fun to speculate with over a month before the trade deadline. 

Michael Lorenzen, Colorado Rockies
Does anyone else feel like Lorenzen should have played on the Cubs by now? Knowing how the front office operates, he seems like a perennial free agent target for this team. The Rockies aren’t a bottom-tier defensive team, placing 17th in the league in team DRS, but Coors Field is not doing Lorenzen any favors. He has an unsightly 6.83 ERA, and his FIP is 4.70, but, shrug: Coors. He is on an expiring contract, and could easily be cut or moved to the bullpen once the incumbents get healthier. The 23-year-old Triantos is having a solid season in Triple-A Iowa, and would probably get called up to the bigs this year with the Rockies.

Michael Wacha, Kansas City Royals
Wacha is in the midst of another strong season for the last-place Royals, one of three teams in baseball to have eclipsed the 50-loss mark on the season. Wacha leads the team in innings pitched with 108 2/3, and has the lowest ERA of any starter on their staff, at 3.31. He is also pitching with a defense behind him that ranks 20th in DRS. On the Cubs, this is a guy who could not only improve their depth but actually provide meaningful innings in the postseason. Since he is owed $14 million next season, the Royals might jump at the chance to move him. They don't have a ton of offensive promise in their pipeline, and may be inclined to take a shot on a package headlined by Long, with Southisene as a throw-in. 

Jack Flaherty, Detroit Tigers
Flaherty exercised a player option to remain with the Tigers for 2026, and his career has been a rollercoaster since being traded from the Cardinals in 2023. He missed some time this season with abductor inflammation, and has a middling 4.35 xERA on the season, but this is another example of an un-sexy addition that could do at least marginally better in front of the Cubs’ defense. The Cubs also have the financial means to eat a significant portion of the $20 million he's being paid this season, and should be able to acquire him for a package around a lottery ticket like Cepeda, while throwing in a lower-level pitcher like Dominick Reid. Flaherty did the best pitching of his career while in the NL Central, so perhaps a return to the division will help him recover some of what made him the ace of the Cardinals’ staff years ago. 

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