Sources: Cubs acquiring pitcher David Peterson in deal with Mets

In dire need of rotation help, the Cubs are acquiring lefty starter David Peterson in a trade with the New York Mets, people briefed on the matter said late Wednesday night after the teams’ doubleheader.

In return for Peterson, who is set to become a free agent after the season, the Mets are acquiring minor-league infielder Cole Mathis.

With the move, Peterson will join a rotation that includes Shota Imanaga, Colin Rea, Javier Assad and Matthew Boyd, who is expected to return from the injured list Thursday to pitch against the Mets.

The trade does not indicate that the Mets are starting a sell-off, according to people familiar with their plans who were granted anonymity so as to freely discuss the situation. The Mets (34-46), however, are amid a five-game losing streak and sitting nine games back of the third wild-card spot, which the Cubs hold.

In moving on from Peterson, the Mets are freeing up a spot in their rotation, recognizing the guys they were using simply were not getting the job done. Earlier on Wednesday, the Mets shifted Kodai Senga, another struggling starter, to the bullpen. Christian Scott is set to come off the injured list Saturday or Sunday and resume a role in the rotation. The Mets, however, would still need to fill a spot. They could pull from their Triple-A group, which includes Jonah Tong and Zach Thornton.

Over 16 appearances, including eight starts, Peterson holds a 6.09 ERA. He was an on-again, off-again member of the Mets’ thin rotation. An All-Star in 2025, Peterson struggled in the second half last year and never found consistency in 2026. Perhaps the change of scenery will help. Peterson ranks in the top 11% in Major League Baseball for ground ball rate, per Baseball Savant, and the Cubs’ infield defense is superior to the Mets’ group.

Given the Cubs’ injury woes, Peterson is a necessary add. Already without Jameson Taillon, the Cubs lost Ben Brown and Edward Cabrera in consecutive days to the injured list. Cade Horton, who finished second in last year’s NL Rookie of the Year voting, underwent season-ending surgery on his right elbow in April. Justin Steele, a one-time All-Star coming off major elbow surgery and a flexor strain, has only just restarted his throwing program, making his full timeline to return unclear.

In 39 games and 182 plate appearances across both levels of Class A, Mathis owns a .981 OPS with 10 home runs and seven stolen bases. The Cubs selected him in the second round of the 2024 amateur draft.

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