Luis Castillo had wanted to play for the Mets for some time before they brought him aboard in a summer trade. By most accounts he fulfilled his obligations: he got on base, played sound defense, and did those #2 hitter things that always draw praise. John Delcos of The Journal News quotes Castillo as saying he wants to come back in 2008.
Presumably the deal would be for something like two years, $10MM. It would add a little stability to second base for the Mets. Delcos says the only other free agent 2B who might rival Castillo is Kaz Matsui, and the Mets won’t be trying that again. I also think Tadahito Iguchi would be comparable to Castillo in many ways. In-house, Ruben Gotay would be the choice.
Don’t forget the trade market though. Orlando Hudson, Freddy Sanchez, Mark Ellis, Jose Lopez, Ray Durham, and Mark Grudzielanek might be available this winter.