Eagles promote RB Matthew Tucker

Philadelphia Eagles running back Matthew Tucker (39) runs past Jacksonville Jaguars defensive end Paul Hazel (79), center, and Jacksonville Jaguars linebacker Brandon Marshall (52) during the second half of an NFL preseason football game in Jacksonville, Fla., Saturday, Aug. 24, 2013.(AP Photo/Phelan M. Ebenhack)

The Eagles promoted running back Matthew Tucker from the practice squad and released cornerback Jordan Poyer on Saturday. The move was made because running back Chris Polk was downgraded from questionable to out for Sunday's game against the Dallas Cowboys with a shoulder injury.

Tucker is an undrafted rookie from Texas Christian who was with the team throughout training camp and the preseason. He has been on the practice squad the entire season. Look for Tucker to be active and contribute on special teams. He'll be the Eagles' third running back.

Poyer, a seventh-round pick, has spent the entire season with the Eagles. He has been active for three games this season. The Eagles could potentially bring him back when Polk gets healthy, or at least add him to the practice squad.

Polk injured his shoulder on a special teams tackle last week and was originally listed as questionable for Sunday's game.