Source: Redskins DL Jonathan Allen out for season with Lisfranc injury

— -- Washington Redskins defensive lineman Jonathan Allen will miss the rest of the season after suffering a Lisfranc injury in his left foot during Sunday's win over San Francisco, a source said Wednesday.

It's a crushing blow for a defense that had been improving, in part because of Allen's performance.

Allen, the 17th overall pick in this year's draft, visited noted foot specialist Dr. Robert Anderson on Tuesday. Redskins right tackle Morgan Moses had a similar injury near the end of the 2014 season, but underwent surgery and returned for the start of training camp.

The Redskins (3-2) play at Philadelphia on Monday night and could be without three key defensive players. Josh Norman (rib) missed Sunday's 26-24 victory and fellow cornerback? Bashaud Breeland?had to leave early after spraining the MCL in his left knee.

Allen had been starting as a tackle in the nickel package, usually playing alongside Matt Ioannidis. The two had been giving Washington what it needed: players who can drive offensive linemen back and collapse the pocket.

Allen only had one sack, but he had a number of strong rushes to help set up others -- or prevent the quarterback from escaping. Those two, plus the outside linebackers, enabled Washington to often send just four rushers and focus on coverage.

On Monday, head coach Jay Gruden said Allen was playing the position "like a veteran, really."

"He has got great fundamentals," Gruden said. "He's got a great idea of run/pass, how to get off blocks. He has got strong hands and he was getting a pretty consistent pass-rush push. He doesn't have a lot of sacks obviously, but he was getting push in the pocket which was critical for the interior guys so the edge guys can get home. Just all around, he has played well."

Allen had fallen in the draft in part because of concerns about his shoulders. The Redskins did not share those concerns and were ecstatic that he fell to them. He provided them with versatility, too; Allen also played end in their 3-4 base front and could line up at different spots. He also occasionally rushed from a standing position behind a nose guard, picking his spot where to rush.

Second-year player? Anthony Lanier II?will replace Allen in the lineup. The Redskins like his length and the fact the 6-foot-6 Lanier he bulked up to 286 pounds; Gruden said Lanier is much stronger than he was as a rookie. He can play tackle in their nickel package and end in their base. He's also considered a good athlete, but more raw than Allen.

Washington's defense is allowing just 88 rushing yards per game, the eight-best total in the NFL. Philadelphia's offense is fifth with?132.5 rushing yards per game.