Was this really a PC decision not to play Jimmy, or was it ultimately DA's call? I haven't seen anything to indicate either.

The offensive coordinator should always have the call on what players are executing his offense if they a medically available and on the 53 man roster (as has been Graham). At least from what I have always gathered. I cannot imagine a scenario where the de facto defensive coordinator (Dennis Allen) would make that call.

Look at it this way, who are you going to sit out of the gameday roster at TE if you were Carmichael? Juwan Johnson? Taysom? Foster Moreau? Or Graham? Moreau is arguably the best blocker with Taysom probably being the next best. Sounds like Graham's just been the odd man out.