What happened: David Peterson posted an Instagram message thanking the Mets organization, his teammates and fans after his trade to the Cubs, writing that it was an honor to wear the uniform and that the relationships he built will last a lifetime. The left-hander, dealt last week for minor-league infielder Cole Mathis, spent his entire big-league career in Queens after debuting in 2020.

Why it matters: Peterson was the longest-tenured Met before the move, making the goodbye a notable close to a six-season run with the only franchise he had ever known. His exit underscores New York's shifting direction while handing Chicago a rotation arm at a moment of real need.

What to watch: Watch Peterson's next turn in the Cubs rotation to see whether he can stabilize a staff thinned by injuries, and how New York fills the innings left behind.