I don't think it's a protest or holdout. Bakhtiari isn't a malingerer and by all accounts has bought into being in GB and working hard. Nothing he has said indicates otherwise either. His vendetta vs. turf goes back much earlier than this year, he's just more vocal about it.

I think his knee doesn't react well to playing on turf, and it's also sore. They put him on the inactive list for the ATL for both reasons, and that's probably it.
Hopefully he can play vs. NO for the home opener.

I wouldn't read too much into it beyond that. Not yet anyway.