Lions head coach Jim Caldwell labeled the injury as "significant" following Sunday's game, and NFL Network insider Ian Rapoport confirmed its severity the following day.
Hyder was rushing Colts quarterback Scott Tolzien before his left leg appeared to give way, leaving the 26-year-old laying near the goal line. Hyder was carted off the field and replaced by undrafted rookie Jeremiah Valoaga.
An undrafted free agent, Hyder collected 36 tackles, a team-best eight sacks and a pass breakup in 16 games during his rookie season.
The loss of Hyder adds to the woes of the Lions, who have fellow defensive end Ziggy Ansah on the physically unable to perform list and top free-agent addition Cornelius Washington battling an ankle injury.