Shortstop was a major problem for the Mets in 2013, with Ruben Tejada injuring himself early on in the season, and backup Omar Quintanilla proving that he isn't anything more than a bench player. Besides first base, shortstop will likely be the biggest position to upgrade on for Sandy Alderson, and based on his recent comments about Tejada's work ethic, it sounds like he'll be acquiring an outside player sometime this winter.
The players he should be interested in include:
Starlin Castro --- Chicago Cubs /.245/.284/.347/ 10 HR/ 161 games.
Starlin Castro was considered a budding star in the league only a few years ago, but a rough 2013 season really diminished his value. He is still only 23 years old, and the Cubs will most likely be looking at a package of pitching prospects for him. I would easily give up someone like Rafael Montero and others to bring Castro to Queens. He is under a team friendly deal, and despite being known as a possible head case, he would be a huge upgrade over Tejada and Quintanilla, and when he's at his best he is arguably a top 5 shortstop in the game. Also, it is worth mentioning that he's on the market because the Cubs have a nice prospect by the name of Javier Baez who is the real deal, and almost major league ready.
JJ Hardy --- Baltimore Orioles / .263/.306/.433/ 25 HR/ 159 games.
Hardy may be a backup option, but a good option nonetheless. I've always liked his power stroke, especially for a shortstop, and he is under a team friendly deal as well. If the Mets are looking for a shortstop with power, Hardy is one of the guys they should be looking at. The Orioles would probably give him up for some rotation help, which is exactly what the Mets have to offer.
Elvis Andrus --- Texas Rangers /.271/.328/.331/ 4 HR/ 156 games.
A few months ago, I supported the idea of bringing in Andrus because I liked his speed and defense. However, at this point, having looked at his contract details, I don't know if he would be the right option for the Mets. Texas will definitely be shopping him this winter with the emergence of top prospect Jurickson Profar, and the Mets may show interest, but I think the Mets could do better than him.
Erick Aybar --- Los Angeles Angels /.271/.301/.382/ 6 HR/ 138 games.
Aybar has been relatively consistent throughout his 8 year career, and would give the Mets solid defense and decent speed. He would be a good leadoff hitter for the team, as he's a switch hitter. The Angels are reportedly going to trade Aybar and/or Howie Kendrick this winter, so he'll definitely be made available. Like the other teams on this list, the Angels are looking for pitching, so perhaps the Mets could dangle some of their lower-tiered pitching prospects to get Aybar.
Troy Tulowitzki --- Colorado Rockies /.312/.391/.540/ 25 HR/ 126 games.
Tulowitzki would be the ultimate pickup for the Mets this winter. I can understand why most people would be reluctant to acquire him, due to his health history and huge contract. However, I would imagine that Colorado would try to unload his contract this winter, and probably kick in some money, perhaps even half, to make a deal happen. Colorado needs major league ready players, so the Mets could offer a package around Rafael Montero, Daniel Murphy, and Dillon Gee. Not many shortstops are capable of hitting over 30 homers in a season while playing outstanding defense, so the Mets should certainly consider him.
Stephen Drew --- Boston Red Sox /.253/.333/.433/ 13 HR/ 124 games.
I've never been a huge Drew fan because of his injury problems, but if he stays healthy he could be a solid upgrade for New York. He has a history of being a great hitter, but hasn't shown that success over the last few seasons. I highly doubt the Red Sox will bring him back, since they have top prospect Xander Bogaraets ready to be called up next season. Drew can probably be had at a reasonable price, and I personally think he'll end up being the one the Mets choose to sign.
Johnny Peralta --- Detroit Tigers /.303/.358/.457/ 11 HR/ 107 games.
Peralta got himself into some big trouble when he was announced in the Biogenesis reports earlier in the season. He played really well up until his suspension, and I feel like he still has something left to offer. He doesn't have much of a power stroke anymore, and I wouldn't say his defense is anything above average, but I would gladly sign him to a one year deal and see if he can rebound himself. The problem is, I don't know if he'll settle for a one year deal, and I would imagine that other teams out there would be willing to give him a multiyear commitment. I do know one thing for sure though: the Tigers will NOT be resigning him, since they acquired young star-in-the-making Jose Iglesias.