DETROIT -- Detroit Lions defensive end Trey Flowers is in the league's concussion protocol and center Frank Ragnow is being evaluated for a concussion, Lions coach Matt Patricia said after the team's 35-27 loss to the Dallas Cowboys on Sunday.
Both suffered the injuries in the fourth quarter. After the game, Flowers was not allowed to speak with the media -- part of the league's policy with the protocol.
Flowers appeared to be in considerable pain as he was helped off the field but seemed to be moving OK in the locker room after the game. Ragnow was not spotted in the locker room after the game.
If the Lions were to lose Flowers for any period of time, it would be a major issue for Detroit's already flailing defense. Flowers is tied with linebacker Devon Kennard for the team lead in sacks, with five, and has a team-best 13 quarterback hurries. Detroit is already dealing with injuries to defensive linemen Romeo Okwara and Da'Shawn Hand, both of whom were inactive Sunday, and recently placed Kevin Strong on injured reserve.
If Ragnow were to miss any time, Graham Glasgow would slide over to center and Kenny Wiggins would fill in at guard instead of rotating in as he does when all four interior offensive linemen are healthy.
The Lions also lost safety Tracy Walker to a knee injury against Dallas -- a few days after he returned to practice for the first time after suffering a knee injury against the Giants on Oct. 27. Patricia didn't know whether or not it was an aggravation of the same injury at this point.
"We had done a couple of things with him through the course of the week and just really saw everything look normal from a physical standpoint," Patricia said. "So had a couple packages that we thought would be good for him to be in."
Walker had told ESPN on Friday that he felt "good" after practicing for the first time and that he was just waiting for the doctors to clear him to play.