LeSean McCoy, here getting past Perry Riley Jr. on a nine-yard run, was frequently matched up on linebacker in pass routes during Sunday’s game. (Toni L. Sandys/The Washington Post)

Defensive coordinator Jim Haslett said Thursday there was “a blown assignment” during the Washington Redskins’ loss Sunday at Philadelphia on the play on which Eagles running back LeSean McCoy had a long gain on a catch while being covered one-on-one by linebacker Ryan Kerrigan.

Haslett did not specify what the missed assignment was.  But he suggested that the Redskins could have stopped the play if they’d executed the defensive call properly as they did, according to Haslett, in a similar situation that resulted in linebacker London Fletcher sacking Eagles quarterback Nick Foles.

“We ran it 10 times during the game and he covered him like six other times,” Haslett said of the Kerrigan-McCoy matchup. “We did have a blown assignment on it on that play. … We ran the same play and London got the sack — same exact play they ran versus the play we ran, he got a sack. So we missed an assignment on it. It probably wouldn’t have happened. It’s one of those situations where we ran it 10 times during the game and we just had a missed assignment that got him open.”

McCoy beat Kerrigan for a 49-yard catch to set up the Eagles’ first touchdown in their 24-16 triumph.

The Redskins did manage to limit McCoy to 77 rushing yards on 20 carries Sunday, one game after they surrendered a relatively modest 75 rushing yards to Minnesota Vikings tailback Adrian Peterson on 20 attempts. Next up is San Francisco’s Frank Gore, as the Redskins face three of the league’s current top seven rushers in a three-game span.

“I thought we did a good job on McCoy,” Haslett said. “We’ve faced three of the best in the league back to back to back here. I think Frank’s different than Peterson and obviously McCoy’s a jump-around guy [who] jump-cuts you and all that. This is different. This is a violent runner who goes downhill. He hides behind people. He has great power and strength, great leg drive. It’s a different type of guy. But we’ve seen three of the best the last three weeks. So this is a great test for us because I think we’ve done a pretty good job on the other two.”

Have a Redskins question? E-mail Mike Jones at mike.jones@washpost.com with the subject line “Mailbag question” for him to answer it in The Mailbag on Tuesdays.

What’s ahead:

● Offensive coordinator Kyle Shanahan speaks to reporters today as well

More on the Redskins:

D.C. Sports Bog: Debating Wilbon’s take on Redskins dramaMore

Fletcher hasn’t decided if he will retire following the season

Griffin deals with a new opponent: criticism | QB  says he wasn’t taking shots

Boswell: Shanahan’s poor defenses with Redskins, Broncos speak volumes

Redskins: No split in the locker room | Joe Jacoby a Hall of Fame semifinalist

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