(ALLEN PARK) – 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. 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. If Ragnow were to miss any time, Graham Glagow 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.