PITTSFORD, N.Y. - The Buffalo Bills have place three players on the active/non-football injury list, including Pro Bowl defensive end Mario Williams.

Cornerback Leodis McKelvin and kicker Dan Carpenter were also placed on the list, which is designated for injuries sustained outside of team activities.

The Bills did not disclose the nature of the injuries. Because they were placed on the list, the players can practice as soon as they are medically cleared.

McKelvin missed the final six games of last season because of a broken ankle. He underwent off-season surgery and sat out the Bills' spring practices.

Carpenter also had off-season surgery for an undisclosed injury.

Williams, who has started every game in his three seasons with the Bills, participated in the team's off-season activities.

Buffalo opened training camp Thursday with meetings and physicals at St. John Fisher College in suburban Rochester, and will begin practice Friday.

The Bills also placed tight end Chris Manhertz and cornerback Cam Thomas on the active/physically unable to perform list.