PITTSFORD, N.Y. (AP) _ Buffalo Bills rookie linebacker Alvin Bowen sustained what's initially been diagnosed as a severe right knee injury in practice today, and coach Dick Jauron expressed fear that the player could miss the rest of the season.

"It doesn't look like it's going to be a good one, but we'll wait and see, but anticipate that he's not going to be playing much football this year," Jauron said.

The Bills' fifth-round pick out of Iowa State, Bowen was hurt during 7-on-7 drills while pursuing fullback Jonathan Evans, who had just caught a pass at the left sideline. When Bowen pulled up to avoid contact, his right cleat stuck in the turf, his knee buckled and he fell awkwardly to the ground yelling in pain.

Bowen lay on the field for several minutes while he was attended to by the team's medical staff. Aware that the injury was serious, safety Donte Whitner also came by to console Bowen.

Requiring assistance to get up, Bowen was unable to put any weight on his right leg as he was loaded into a cart and driven to the team's nearby training camp facility. Jauron said Bowen was resting comfortably and was expected to be taken to a Rochester-area hospital for tests.

Bowen was competing for a backup spot and a regular role on the Bills special teams unit.

Selected 147th overall, Bowen was an All-Big 12 Conference first-team selection in both his junior and senior seasons. He led the nation with 155 tackles in 2006 and finished with nine sacks in 46 career games.

Free safety Ko Simpson returned to practice Friday, a day after he missed practice to have tests on his left ankle. Simpson said the tests showed only a bone bruise on his foot.

Rookie receiver James Hardy practiced on a limited basis a day after he hurt his left hamstring.