Detroit placed the defensive end on the physically unable to perform (PUP) list ahead of Wednesday's report date, the team announced Monday. The injury appears to be minor and Flowers didn't do much work at OTAs last month, per NFL Network Insider Ian Rapoport.
Dave Birkett of the Detroit Free Press is reporting this as a shoulder injury. Flowers underwent minor shoulder surgery before free agency opened.
Players on the PUP list may participate in team meetings and utilize team facilities, but are unable to practice with the team. A player can be removed from the list at any time.
The former fourth-round pick had a career-high 7.5 sacks and three forced fumbles in 2018. He is expected to be a key starter for Patricia's defense this season.