Being a baseball general manager is a thankless job. Every move that you make is second-guessed, critiqued and analyzed to death before a new player even steps out onto the field. Then there's the separate issue of what to do with your hometown players, some of whom have evolved into local legends or fan favorites.
Every player has to become a free agent eventually, but the gut-wrenching question facing every general manager is when is the right time to let those players go? In the case of these 15 players, their GM's let them go too soon.
For the sake of this list we'll eliminate players who had no chance of re-signing with their former teams (Jayson Werth, Carl Crawford) and players that teams made an effort to sign but were outbid (Cliff Lee).