Detroit Lions defensive end Trey Flowers was placed on the physically unable to perform list with an undisclosed injury ahead of training camp, the team announced Monday.
Veterans are scheduled to report to camp Wednesday.
The 25-year-old was excellent for the Patriots in his first three seasons in the NFL, with 164 tackles, 21 sacks and five forced fumbles. He made himself a key cog in New England's defensive line rotation, showing the versatility throughout his career to play both on the edge and occasionally as an interior rusher on obvious passing downs.