A healthy Hanley Ramirez would most certainly be a great fit for the Mets at shortstop. Of course, he's only played one full season since 2011 due to various injuries, and let's not even mention that his asking price will more than likely be way out of the Mets' price range. Fangraphs estimates Ramirez's contract value to be in the neighborhood of five years, $90 million.
Ramirez is a dynamic player at full strength. In just 86 games in 2013 with the Los Angeles Dodgers, he hit .345 with 25 doubles, 20 home runs, 57 RBI, and ten stolen bases, while amassing a staggering 5.4 fWAR in what amounts to a little over half a season of action. He came down to Earth in 2014, but still managed to hit .283 with 13 homers and 71 RBI in 128 games, while battling through a strained oblique and other minor injuries.
The former National League batting champion and 2006 Rookie of the Year is clearly the best position player on the free agent market. Ramirez will be 31 at the start of the 2015 season, and despite his injury history he should have very little trouble finding a lucrative contract. The Seattle Mariners have shown interest and other teams are sure to get involved since Ramirez has expressed his willingness to shift to third base or another position if needed.
The Mets, who are notably light on production at shortstop, would love to have a player of Ramirez's talents at Citi Field. The asking price will almost certainly be a nonstarter, though, so they will doubtless look elsewhere for an upgrade or just forge ahead with Wilmer Flores as their starter.