Pitcher David Peterson has been traded to the Chicago Cubs, marking a significant roster move for the New York Mets as the Aug. 3 trade deadline nears. Peterson, who was the longest-tenured player on the Mets, was sent to Chicago in exchange for infield prospect Cole Mathis.
The trade was confirmed shortly before midnight on Wednesday. Peterson, a left-handed pitcher, had spent his entire Major League Baseball career with the Mets since his debut in 2020. He was expected to start for the Cubs this weekend in Milwaukee. Cubs manager Craig Counsell acknowledged the surprising nature of the trade for Peterson, noting that he could sense the adjustment in his voice during a phone call.
"Nobody tells you when you’re gonna be traded," Counsell said. "They call you into the office or they call you on the phone and say, ‘You’ve been traded.’ That’s the warning you get. That’s shocking news for anybody. So I think he’s feeling the effects of that, and that takes a little while."
For the Mets, who entered play with a five-game losing streak and in last place in the National League East, this move signals the beginning of potential changes to the current roster. Peterson's departure could be the first of several before the deadline.
Peterson had been an integral part of the Mets' 2024 National League Championship Series run and was an All-Star in 2025. However, his performance has stalled this season, leading to a role change to a bullpen piece and bulk-inning reliever. He holds a 6.08 ERA through 16 appearances, including eight starts, this season. His last outing on Sunday against the Phillies was particularly difficult.
Mets manager Carlos Mendoza stated that Peterson's reaction to his role did not influence the trade decision. Mendoza praised Peterson's adaptability and willingness to fulfill team needs. Peterson, a first-round pick in 2017, struggled with consistency, posting a 2.41 ERA in the final two months of the 2024 season and a 2.83 ERA through his first 20 starts in 2025, earning him an All-Star selection. He was intended to provide stability in a rotation that experienced inconsistencies from pitchers like Kodai Senga and unproven prospects.
"And then kinda everything went the other way," Mendoza said. After allowing 14 earned runs in 14 1/3 innings over a three-start stretch, Peterson was moved to the bullpen, making four starts from that role and also pitching bulk innings in other games.
"It’s a tough one," Mendoza added. "because obviously, you understand this is a business. But especially from my end, I had a really good relationship with [Peterson]. … But it got to a point where needed the flexibility on the roster. Talking to David [Stearns], we already have Kodai in the pen and just continue to have starters in the bullpen, it’s just not gonna be sustainable."
Cubs manager Counsell expressed optimism that Chicago's strong defense, in contrast to the Mets' recent struggles with errors, could benefit Peterson, who tends to induce ground balls. The Cubs saw the trade as a way to fill a need with five weeks remaining until the deadline.
The Mets are left with a void in their pitching staff and a new longest-tenured player. This situation serves as a reminder that further roster changes are possible before the trade deadline. Despite the uncertainty, outfielder Bo Bichette downplayed any pressure to win before the deadline, stating, "We’re just focused on winning as many games as we can. We can’t really focus on all that kinda stuff. We just have to focus on what we can do today."