Safety Brandon Meriweather said his injured left knee is improving but he remains uncertain when he will be able to practice at full speed or return to the Washington Redskins’ lineup.

“I’m better than I was last week,” Meriweather said Monday.

Meriweather, who has missed the Redskins’ first two games, said he is going to try to get ready to play this week.

Brandon Meriweather (Jonathan Newton/The Washington Post)

He originally injured his knee in the second preseason game at Chicago. Meriweather returned and was practicing fully before the regular season. But six days before the Redskins’ season-opening win at New Orleans, he landed awkwardly on his knee and re-injured it by suffering sprained medial collateral and posterior cruciate ligaments. Redskins Coach Mike Shanahan said at the time that Meriweather would be sidelined for two to four weeks.

Meriweather said Monday he doesn’t know when he’ll be able to resume practicing fully.

“I have no idea,” Meriweather said. “If it was up to me, I would have been [practicing fully] last week.”

The Redskins were without four defensive starters by the end of Sunday’s loss at St. Louis: Meriweather, cornerback Josh Wilson, linebacker Brian Orakpo and defensive end Adam Carriker.

Wilson suffered what Shanahan described Sunday as a mild concussion. Under NFL rules, he will have to be cleared by an independent neurologist before he can practice or play in a game.

The Redskins don’t expect Carriker to play again this season because of his injury to his right leg and expect Orakpo, who appeared to aggravate an injury to his left pectoral muscle, to miss at least one game.