Lions coach Jim Schwartz said Scheffler, who didn't practice all week, wasn't even at the team's facility Friday.
In other injury news, star receiver Calvin Johnson, who has been battling a knee injury, is officially listed as questionable for Sunday's game and will be a game-time decision.
Schwartz just shook his head when asked whether Scheffler or rookie running back Theo Riddick, who also suffered a concussion Sunday, were closer to being cleared. He also couldn't determine if either player would be out for an extended period of time.
"You never know," Schwartz said. "That's the nature of that thing, of concussions. I've beat this drum too much, too. It's not like a situation with a hamstring or a shoulder. If your shoulder is hurt, it's pain tolerance and you can get out there and you can contribute, let's go do it. If your hamstring's tight, you're not quite full speed but you can still contribute, you go out and do it.
"Concussion, there's no shades of gray as far as playing. We're just going to take it as it comes and plan accordingly."
The news is better for Johnson, who has practiced the past two days -- without a knee brace for the media portion Friday -- after missing Sunday's game against Green Bay with a right knee injury.
"I don't really want to comment on how much he was able to do," Schwartz said. "But he is getting better every day and we'll see when we get to Sunday what he looks like.'
If Johnson can't play, expect Detroit to use more of Kevin Ogletree on the outside after signing him last week. The Lions also will lean more on rookie tight end Joseph Fauria and multiple-wide receiver sets to compensate for Scheffler's absence.