NFL Network's Ian Rapoport provided an update following the official announcement:
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.
That made him one of the top free agents to hit the market in the 2019 offseason, and the Lions pounced, signing him to a five-year, $90 million deal.
He was expected to be a major difference-maker in Detroit, with Pro Football Focus naming him the 46th best player in the NFL heading into the 2019 campaign:
"Improving steadily every year of his career, Flowers earned career-high marks in overall grade (89.7), run-defense grade (84.9) and pass-rush grade (79.9) a year ago. He also finished the 2018 season ranked tied for eighth in pass-rush win percentage (17.4 percent) and sixth in pressure percentage among the 61 NFL edge defenders with 300 or more pass-rush snaps played."
That obviously makes any injury to Flowers a major concern for Detroit as the Lions seek to integrate their prized free-agent signing and start the 2019 season on the right foot.