King Dunlap missed his second practice in a row Friday and was listed as questionable on the Eagles' injury report for Sunday's game at Washington.
Dunlap has had back spasms and if they don't calm down by Sunday Todd Herremans will move from right tackle to left tackle and Winston Justice will get his first start of the season at right tackle, Andy Reid said.
Justice underwent arthroscopic knee surgery in February but the recovery period has been longer than many originally expected.
"It seems like every week he's getting a little bit better and feeling more comfortable," Reid said. "So he deserves the opportunity to play if that presents itself."
Justice declined to comment specifically about his knee. Reid said that Dunlap could play Sunday even though he didn't practice Thursday or Friday. "King's a smart kid," Reid said. Dunlap started last week in place of Jason Peters (hamstring), who is out again this week.
Herremans has played left tackle before but not much in the NFL. He, of course, has spent most of his career at left guard before being moved to right tackle just before this season. If Dunlap can't go left guard Evan Mathis would be the emergency tackle, Reid said.
Defensive end Juqua Parker (ankle) practiced and was listed as probable. Defensive end Trent Cole (calf) did not practice and it out along with Peters.
Eagles tackle King Dunlap wasn't involved in the early portion of Friday's practice, putting his availability for Sunday's game at Washington in question.
Dunlap showed up at the team's indoor facility during practice but wasn't wearing pads or a helmet. He was likely there to get in some mental repetitions. Dunlap practiced Wednesday and wasn't listed on the injury report afterward, but the team said back spasms kept him out of Thursday's session.
With Dunlap sidelined, Todd Herremans moved over from right tackle to left tackle and Winston Justice jumped up and took Herremans' place at Thursday's practice. Justice hasn't played all season, but was active last week for the first time. He spent all of the preseason on the physically unable to perform list because of off-season knee surgery and is still walking with a limp.
The Eagles have no other tackles on the 53-man roster, although both starting guards -- Evan Mathis and Danny Watkins -- have played tackle before. Mathis was briefly at right tackle in training camp and Watkins played left tackle in college at Baylor.