ORCHARD PARK — Miami Dolphins running back Knowshon Moreno hurt his left elbow on his first carry against the Buffalo Bills on Sunday .

The Dolphins announced Moreno and would not return.

Driving up the middle for a 4-yard gain, Moreno was initially hit on the right side by safety Nickell Robey. Linebacker Nigel Bradham then struck Moreno from the left, hitting him directly in the arm.

Moreno immediately clutched his left forearm as he lay on the field. He was attended to by trainers and then escorted to the locker room.

Moreno was a key offseason free-agent acquisition. He had an NFL-leading Week 1 best 134 yards rushing and a touchdown in a 33-20 win over New England.