Six Mets filed for free agency Monday, on the first day players were eligible: Marlon Anderson, Luis Castillo, Ramon Castro, Damion Easley, Shawn Green and Paul Lo Duca. The Mets figure to make re-signing Castillo a priority after trading for the second baseman at the July 31 deadline. Lo Duca wants to return, but Mets' brass, while not ruling out a return, hopes to instead acquire a catcher via trade.