1. Happ doesn't take well to being dicked around - too bad, do what's best for the team. If he stinks it up again he should be moved to the pen as swing man
2. Although the rotation is "full" right now, the schedule is relentless with 16 consecutive game days from now till the all star break. Given Hutch and Dickey being iffy recently with possible stamina + groin issues, giving someone a couple of spot starts might make sense.
If I need such spot starts over the next 2.5 weeks I'd pick Drabek, not Hendriks or Rogers (bad) or Nolin (injured)