The Washington Post’s Mike Jones breaks down the Redskins’ loss against the Seattle Seahawks and Robert Griffin III’s injured knee. And find out what the team needs to do in the offseason to stay competitive next year. (The Washington Post)

There is no telling what, precisely, caused the injury to Robert Griffin III’s right knee in the fourth quarter of the Washington Redskins’ playoff loss to the Seattle Seahawks on Sunday. Seahawks defensive end Chris Clemons tore his anterior cruciate ligament on the same surface, and he is out for the remainder of the postseason — whether the turf caused the injury or not.

What’s not in doubt: FedEx Field’s playing surface looked, to the eye, to be in poor shape, and Seattle Coach Pete Carroll was unhappy about it.

“It was horrible,” Carroll told ESPN 710 in Seattle on Monday. “It’s a horrible field. It’s as bad as a field can get for being dry. And it’s too bad.

“It’s really too bad, and we deserve better. . . . It just was worn out. And there was a lot of slipping and all that kind of stuff.”

The midsection of the playing surface at FedEx Field, which hosted its first playoff game in 13 years Sunday, appeared worn down.

Ligaments work to allow the knee to bend forward while limiting its ability to rotate and flex side-to-side. On the play in which Robert Griffin III was hurt, the lower half of his knee makes both of those movements to excess, suggesting an injury to the anterior cruciate ligament.

The Redskins logo at midfield was barely visible.

Griffin, who suffered an injury to his already balky right knee in the fourth quarter, was asked Sunday about the condition of the surface.

“It’s just part of our home-field advantage,” he said, smiling.

The NFL has a standard operating procedure in place to evaluate playing surfaces prior to competition. The Redskins, the league said, followed proper protocol in this case.

“It’s the responsibility of the home team,” NFL spokesman Greg Aiello said. “The home team must certify prior to each game that the playing field meets certain conditions.

“The Redskins certified their compliance prior to the game.”

According to the NFL’s game operations manual, a field must pass inspection within 72 hours of hosting a game. It must pass tests for firmness and evenness of surface.

According to the manual, “Failure to comply is considered a competitive as well as a player safety issue and will be subject to disciplinary action by the Commissioner’s office.”

Redskins Coach Mike Shanahan has been asked about the field in recent weeks as the surface appeared to deteriorate. He said he has, in the past, had both good and bad experiences with re-sodding playing surfaces.

On a day dominated by queries about the extent of Griffin’s injury, Shanahan said Monday he is open to discussing an artificial surface, “but I do like natural grass.”

He said the issue would be addressed prior to the 2013 season.

“I’ve seen perfect grass and guys just slipping all the time,” Shanahan said. “And so therefore I don’t think there was an advantage one way or disadvantage one way.

“But you would like to have the perfect field, yes.”

Carroll said in the same radio interview that he did not think the surface impacted the outcome of the game.

“It didn’t change the game at all, in my opinion, because it was relative, both sides,” Carroll said. “But we should just expect to see a better field at that time of year.”

Minnesota Vikings running back Adrian Peterson suffered a torn anterior cruciate ligament on Dec. 24, 2011 in a game against the Redskins at FedEx Field. Peterson returned this year to lead the NFL in rushing, falling nine yards short of the all-time record.

FedEx Field hosted a Kenny Chesney-Tim McGraw concert in August and two college football games — Cincinnati against Virginia Tech and James Madison against West Virginia — in September. It has not hosted soccer since a U.S.-Brazil men’s match in May.