ESPN first reported Tuesday night that Lynch has experienced back spasms and the team is uncertain whether he'll be able to play in the team's first regular-season game Sunday.
Speaking to reporters after Wednesday's practice, Carroll confirmed that it's still questionable if Lynch will play.
"We really won't know until the end of the week, unless something changes," Carroll said of Lynch. The process he's gone through -- he's aerobically in good shape. We need to get him back to his football legs. We'll just have to wait and see. I can't call it for you now."
Lynch missed practice Monday and hasn't played since the second week of the exhibition season.