This scenario reminds me of this quote about Peyton Manning when he was on the Colts.
As we watched, we were surprised to see Manning taking virtually all the reps in the session. Jon [Gruden] asked Tom [Moore, the Colts offensive coordinator,] why he wasn’t giving some snaps to Peyton’s backups…He looked at us both in the eye, paused for a moment, then said in that gravelly voice of his, “Fellas, if ‘18’ goes down, we’re fucked. And we don’t practice fucked.”