Miller carted to locker room, reportedly diagnosed with knee sprain
The initial diagnosis for Miller is a knee sprain, a source told Ian Rapoport of NFL Network. With a more serious injury reportedly still not ruled out, Miller will undergo an MRI and other tests Friday.
Miller had his right leg rolled up on by a Lions offensive lineman toward the end of the first half.
The All-Pro linebacker recorded one tackle and one quarterback hit before exiting.
Entering Week 12, Miller led the team in sacks (eight) and quarterback hits (11) in his first season in Buffalo. He also had one forced fumble and 20 total tackles.
The 33-year-old was the prized free-agent addition of the Bills' offseason after helping the Los Angeles Rams win the Super Bowl last season.
If Miller misses significant time, it would be a major blow to the Bills, one of the top Super Bowl contenders.