Leave him in AA but bump him up to AAA if they need an extra player for the pennant race. Same for anyone else in AA at this point in the season (Rosario, Meyer, May, Santana, Ortiz, etc). There is less than a month left in the minor league season. The only player on the 40 man roster who hasn't been with the Twins yet that merits a Sept callup is Josmil Pinto. Gardy would love having four catchers on the roster.