It sounds like the plan is to run alternate training sites in April, and possibly longer for teams where there's some distance between the MLB team and the AAA affililate. You've already got an entire AAA/AAAA team in Clearwater now, so they will just break camp when the big-leaguers do and head to Allentown. So-called "minor league spring training" will only be for the guys who have yet to report (and all the lower level players).
So if Howard doesn't crack the rotation he - or Anderson, as well as guys like Nova and Mitchell, and prospects like Medina/Rosso - will just get on turn in simulated intrasquad games, just like last season. In Howard's case it's a waste of innings but that would also potentially be true in real AAA games.