5 NY Mets trades that would swap David Peterson for another starting pitcher

3) Luis Castillo

They say they don’t intend to trade Luis Castillo. When have we ever believed Jerry Dipoto wasn’t going to trade someone? Two more guaranteed years at just over $24 million with a vesting option for $25 million in 2028, he’s someone the Mets should call about constantly. The Mariners may not want to trade him, but it’ll be tough to improve the rest of the roster without raising payroll. They already aggressively brought back Josh Naylor. Using Castillo as a trade chip in a swap for Peterson is one way to clear some space to add offense or bullpen help.

In fact, maybe Peterson even could be a solution in the bullpen for the Mariners if they felt that was the better role. One-for-one this doesn’t work so well. Castillo is way too proven for the Mets to be able to get him for just Peterson.

Another team who has been involved in the offseason McNeil rumors, they’d probably prefer a young infielder instead. The Mets have this in abundance. Let’s get a deal rolling.

Seattle has been the envy of the league with their deep pitching staff for a few years now. They may take a step back here as far as talent goes, but with the way Peterson pitched to start the 2025 season and their lack of lefty starters, it’s not that bad of a direction to go.

Makes sense if...the Mariners want a competitive way to keep the pitching strong without paying as much into the rotation.