Davis sustained the injury in the first quarter of Friday night's contest against the Bills. He had his right leg rolled up on by teammate Devon Kennard on the Bills' first offensive possession.
Davis fell to the ground and grabbed at his right leg after a run by Bills running back LeSean McCoy. He attempted to walk to the sideline under his own power but couldn't apply any pressure on the leg. Lions trainers carried the linebacker off the field and later carted him to the locker room.
The Lions selected Davis in the first round of the 2017 NFL Draft out of Florida. He has been the team's starting middle linebacker the last two seasons and served as a team captain in 2018.
Davis has started 30 games with the Lions, recording 196 combined tackles, eight sacks, one interception, eight passes defended and two fumble recoveries. He had a career-high 100 tackles and six sacks last season.
Lions center Frank Ragnow, the team's first-round pick last year, was also taken to the locker room after suffering an apparent right leg injury midway through the second quarter against the Bills.
Ragnow is expected to be the Lions' starting center this season. If he misses an extended period of time, the team would likely shift Graham Glasgow from right guard to center.