I think the argument for Jansen at AA instead of AAA has a lot to do with the idea that you get a lot more talented pitchers to hit at AA. AAA is full of more of the journeyman 6th starter types, while AA is full of the raw talent. So it kind of makes sense to try to develop his bat against the better pitchers. Then you have the situation where if you actually plan on Jansen being the catcher of the future, it also makes sense for him to be catching our future pitching prospects in AA, rather than our current 6th-7th-8th men in AAA.