Technically the definition of someone that is on the MLB trading block is a player that is in the final year of his contract. Teams usually like to trade those players during the season so they can get full return on their investment. Those are the reasons that most believe the Atlanta Braves should have tried to trade Brian McCann. He would be worth a ton in return and the Braves are unlikely to resign him after the season. Those rumored to think the Braves missed out here are wrong, however.
There is more to a player than just the value they bring on the open market. Sometimes for a contending team there is more to gain by keeping them than by trading them. Sure the Braves could have gotten a ton in return for McCann but that would have still been nowhere close to what they would have lost. McCann is a leader on the team and is awesome with the pitching staff. Even the top ten prospects in all of MLB wouldn’t replace what McCann could do for the team this season and in the playoffs.
If they lose him this off-season then they just lose him. There is no reasonable reason to think they would consider trading him. Evan Gattis is coming along and probably can take full time catching duties next season but there is no way to replace McCann this season. Over a full season Gattis could learn the ropes well enough to lead the pitching staff through the post season and the stretch run. For the 2013 season, the Braves wouldn’t have even traded McCann for the greatest catcher ever, much less a list of prospects.