This post started as a comment, but I decided it was too long. So I switched it into a front page post. It is possibly even too complicated of a solution, but in my opinion it works as a response to two of the main reasons Jscape came up with:
2) When you call him up, keep him up.
3) Defense counts
Personally I would love to see Montero get called up and stay up. The way I would go about it is demote Francisco Cervelli, which would let him work on his overall catching while using his game calling skills to help out the AAA staff, and keep Martin in the MLB when he gets activated from the DL.
A week would look like this:
Sunday- catcher Russell Martin, DH Jesus Montero
Monday- catcher Montero, DH Martin
Tuesday- catcher Martin, DH Jorge Posada
Wednesday- catcher Montero, DH Posada
Thursday- catcher Montero, DH Martin
Friday- catcher Martin, DH Posada
Saturday- catcher Montero, DH Posada
Montero plays five days a week, catching in four days. If the Yankees don't play on a Monday/Thursday, he plays four days a week and catches in three. The days he does not play in he works with Pena and possibly even catches the bullpen.
Martin plays five days a week, catching in three days. This saves Martin from some injuries, and allows him to still play. Montero should be the main concern, not Martin.
Posada still gets to DH four days a week, and possibly even more if Martin can give A-Rod a day off at 3b and Posada takes one of Martin's DH days. Preferably the weekly schedule would be switched around so that Posada plays against righties, and his off days are against lefties.
Still, this gives Montero a way of staying up for the season, and working on his defense while in the MLB. If Martin is hurt Montero gets more playing time, and if Martin is placed on the DL Montero gets even more playing time, while Cervelli becomes the backup. Martin would likely be let go at the end of the season in this plan, but it is not completely necessary.
If Montero struggles he can be sent down and Martin can go back to catching the majority of the time, or he can work with Kevin Long and Tony Pena in the majors.
One question, does anyone worry about the catcher position being a problem for the Yankees top prospect? I recently heard many analysts saying that top catching prospects should have their position switched so the bat isn't lost if the prospect gets injured. It doesn't seem realistic for Montero, but I wonder if anyone feels that way.