With a must-win game looming in Washington on Sunday, the Eagles are facing a potential offensive line shortage. Philadelphia's starting left tackle Jason Peters is out indefinitely with a hamstring injury he suffered in a loss to the 49ers two weeks ago, and his replacement, King Dunlap, missed a second consecutive day of practice Friday because of back spasms. The two injuries have left the Eagles with only two healthy offensive tackles -- Todd Herremans, the usual right tackle, and Winston Justice, who missed all of training camp because of offseason knee surgery and hasn't played all year.