3) NY Mets prospect Ronny Mauricio can headline a trade for Athletics pitcher Frankie Montas
Frankie Montas is in a similar boat to Luis Castillo. I don't think he's quite as good as Castillo is, but he'd be a third starter that would probably be a two on most teams.
Counting on deGrom to stay healthy is just not possible right now, and the Mets getting another elite arm would be huge.
Montas has posted a 3.16 ERA in 18 starts this season after posting a 3.37 ERA in 32 starts last season. He's a guy you can rely on to give quality innings as he's gone at least six innings in 12 of his 18 starts.
Like Castillo, Montas is a free agent after next season, so with guys like deGrom, Walker, Bassitt, and Carrasco on the team who can all hit free agency after this season, it'll be good to have Montas here confirmed as a starter for next season.
The 29 year old can also be extended and remain in Queens for a while, hopefully alongside his former Athletics teammate Chris Bassitt.
Losing Ronny Mauricio would be unfortunate as he's a shortstop who can hit for tremendous power, but he just doesn't have a place long term on this team. Lindor is locked up at shortstop, Brett Baty is a better prospect than he is at third, and they haven't used him in the outfield.
Trading him is what win now teams do, and I think the Mets are ready to win right now.