ALLEN PARK, Mich. -- The Detroit Lions have lost defensive back Avonte Maddox for the season due to a foot injury requiring surgery, coach Dan Campbell announced Monday. Maddox was injured in the first half of Thursday's 41-31 loss to the Buffalo Bills after a collision with teammate Chuck Clark.

Campbell defended second-year defensive coordinator Kelvin Sheppard, whose defense has allowed 71 points in two games. "I believe in Sheppard. I believe he's an outstanding coach. There's a bump in the road," Campbell said. "I believe they're the right guys to get this thing done."

The Lions (1-1) also remain without starting safeties Brian Branch (Achilles) and Kerby Joseph (knee), both on the physically unable to perform list. Branch could return sooner than Joseph.

Detroit signed veteran defensive back Jalen Mills to the practice squad Monday after a workout that included Jordan Fuller and Mike Edwards. The Lions host the New York Jets on Sunday.