I think there is a big difference between Mesoraco and Tucker. Mes was a first round pick, top prospect and projects to be an All Star caliber player. That's growth that can be significantly stunted. Barnhart is a low level pick, a defensive specialist who projects as a defensive minded back-up. He's already a plus-plus defender. He's probably never going to be much of a hitter. He's not likely to be much more than he already is and at some point he's going to be sitting on a major league bench. Waiting another season or two isn't going to make him any more than the 30 to 40 start per year, defensive minded back-up that he could already be in 2014. Why wait if there isn't a pay-off? More time in the minors would not have ever made Bill Plummer a starter. Barnhart can have a nice career backing-up a solid starter. If they think he's got a chance to hit more than that, then I'm fine keeping him in AAA and bringing in a journeyman, but it's time for Mes to become the 5 days per week catcher.
It's not really a Dusty problem. Mesoraco has outgrown the need for a tandem partner (Hanigan) and needs more of a pure back-up behind him (Barnhart or some other defensive minded 30 start per season guy). Hanigan is going to command a $3 Million or so salary and he's aging. His rapport with some of the existing starting rotation along with his familiarity and salary are going to suggest more playing time than Mesoraco's partner should get. He's past the age where catchers maintain their ability. Want a safety net? Fine, but its time to cut the chord IMO. Trade them a year too soon and not a year too late. Let Hanigan go elsewhere where he can play 45% to 55% of the time, but he shouldn't be that here in 2014.