Bills defensive back Aaron Williams, who set up a field goal with a first-quarter interception, was injured defending a deep pass in the second quarter and was on the sidelines late in the fourth quarter.
Williams leaped to knock down a pass thrown by Baltimore's Joe Flacco and appeared to land on his shoulder. He was holding his arm close to his side as rolled over following the play. He was treated on the field.
He missed one play but then headed to the locker room with two minutes left in the first half.
Williams was able to play on Baltimore's first series in the third quarter but was removed with a lower back injury late in the game.
The Baltimore Ravens also lost a player from their secondary as starting cornerback Ladarius Webb left with a thigh injury. His return is doubtful.