The Lions also kicked off the season without safety Louis Delmas and rookie corner Bill Bentley suffered a concussion after getting the start Sunday.
"I don't know how you'd classify it, because a concussion is a concussion, but he's doing really well," Lions coach Jim Schwartz told MLive.com. "Yes, he has to pass a protocol to be back. That's an objective thing. That's not a subjective, 'Well, we think he's doing fine.' He has some hurdles he needs to cross, but we're optimistic."