There’s little doubt that Andrew Bailey has been effective in his major league career, as evidenced by his 2.64 ERA and 3.13 FIP. In five years in the big leagues between Oakland and Boston, though, he just hasn’t been able to stay healthy over the course of a full season, having thrown more than fifty innings in a season just once and only 44 innings combined in 2012 and 2013.
In that limited time with the Red Sox over the past two seasons, he really struggled, too, particularly when it came to serving up home runs. His home-road splits don't help him much, either, as he allowed home runs at a higher clip on the road than at Fenway Park in 2013.
Still, Bailey will only turn 30 in May, and a move to a flyball-friendly park and the National League could help him bounce back. The Mets' bullpen is far from a sure thing heading into next season, and like most non-tendered players, there's a good chance Bailey can be had at a relatively low cost.