Ashburn, VA (SportsNetwork.com) - The Washington Redskins have placed cornerback Tracy Porter on injured reserve, the team announced Wednesday.

Porter separated the AC joint in his shoulder during Washington's 17-13 loss at San Francisco on Sunday. The oft-injured veteran had previously missed eight of the team's first nine games while dealing with a pulled right hamstring before returning to play in the last two contests.

The Redskins signed Porter in the offseason after he made 16 starts with Oakland in 2013, recording 67 tackles, two interceptions, 1 1/2 sacks and 12 passes defensed.

Cornerback Chase Minnifield was added back to the active roster from the practice squad to take Porter's place. Minnifield appeared in six games with Washington earlier this season prior to being waived on Nov. 4.