ORCHARD PARK, N.Y. -- Buffalo Bills running back Fred Jackson (ankle) and guard Chris Williams (back) were not spotted at the beginning of Friday's practice.

Both players were limited participants in Wednesday's and Thursday's practices.

Jackson suffered a right ankle sprain in last Sunday's win over the Detroit Lions but returned to the game. Williams, the Bills' starting left guard, missed the past two games with a nagging back injury.

The Bills will announce both players' status for Sunday's game against the New England Patriots later Friday.