Buffalo Bills wide receiver Stevie Johnson left Friday's practice session due to a hamstring injury.

The Buffalo News reported that the 27-year-old was running a pass route when he abruptly stopped and grabbed the back of his left thigh. He was helped to the locker room by team trainers for evaluation.

Despite a groin injury suffered just prior to the outset of the 2012 season, Johnson participated in all 16 games last year, totaling 79 receptions for 1,046 yards and six touchdowns.

In addition, tight end Mike Caussin departed practice early due to a sore hip.