Redskins Coach Mike Shanahan said left tackle Trent Williams (ankle) continues to improve, but no determination has been made yet on his availability for Sunday’s game against San Francisco.

Tight end Fred Davis (ankle) did not practice.

Shanahan said quarterback John Beck will remain the starter for a third game.

Shanahan said the team is trying a couple of different combinations along the line to compensate for the banged up left side.

The team picked up Tashard Choice to help meet the need for backfield depth, Shanahan said. Choice has been hampered by a hamstring injury, but Shanahan thinks the back will be able to begin practicing Monday.

Shanahan said of Carlos Rogers, who left the team after last season and was signed by the 49ers: “He was looking for that big payday ... If he played as consistent as we would have liked, we would have re-signed him.”