Expected to be the strength of a team undergoing an overhaul on offense, the Redskins’ defense put on a sloppy performance marked by poor tackling, soft pass coverage and injuries in Sunday’s 31-28 loss to the St. Louis Rams.

The Redskins braced for the likelihood that they will be without one, and possibly two, defensive starters for an extended period of time.

Defensive end Adam Carriker is expected to have to have surgery on his right knee, and outside linebacker Brian Orakpo is believed to have re-injured the same left pectoral muscle that he tore in the 2011 season finale and had surgery to repair during the offseason.

Cornerback Josh Wilson left the game in the third quarter after suffering a concussion.

By the end of the game, the Redskins were down four defensive starters, counting strong safety Brandon Meriweather, who has missed the first two games of the season with a knee injury.

The injuries punctuated a poor showing by the defense that last week opened the season by limiting Drew Brees and the New Orleans Saints’ prolific offense in a 40-32 victory. The Redskins allowed the Rams to rack up 452 yards on offense and to dominate them in most of the major statistical categories.

“Against the Saints, we knew it would be a tough go because of them having an explosive offense. We gave up 32 to the Saints, but that was a win. But giving up 31 today, you definitely don’t feel good about it,” inside linebacker London Fletcher said. “As the captain of the defense, I take responsibility that I need to get my guys to play better.”

The game started on a promising note.

On the first play from scrimmage, Rams quarterback Sam Bradford completed a pass to wide receiver Danny Amendola, who put a move on Redskins strong safety DeJon Gomes, and then picked up 13 yards. But near the end of Amendola’s run, Washington inside linebacker Perry Riley jarred the ball free of the receiver’s grasp. Wilson scooped up the loose ball and went 30 yards to the end zone to give his team a 7-0 lead just 11 seconds into the game.

But on the next play following the kickoff, Carriker — the team’s left defensive end — went down with a right knee injury and had to be helped off of the field. Carriker spent the bulk of the first half watching from the trainers’ table with his knee wrapped in ice. In the second half, he stood on the sideline with the aid of crutches.

“I was rushing the passer, planted on the right leg. . . . I have to see exactly what I was doing, but I just felt a lot of pain,” Carriker said. “I couldn’t really walk or put much pressure on it.”

“It was real hard. This game probably means a little more to me, personally,” added Carriker, who was facing the team that drafted him out of Nebraska in 2007.

Eleven plays after Carriker was hurt, Orakpo recorded a sack and forced fumble on Bradford. But the outside linebacker came up grabbing his left arm. Visibly upset, Orakpo threw his helmet as he came to the sideline, paced back and forth in front of the bench, and then took a knee and grabbed his arm again.

Orakpo took his shoulder pads off and was tended to on the trainers’ table with Carriker sitting next to him. Orakpo tried to return in the first half before leaving the game again and heading to the locker room. He came back to play the first two defensive snaps of the second quarter, but then left again and didn’t return.

Carriker is to have an MRI on Monday, but Coach Mike Shanahan indicated that the team isn’t optimistic about his chances of returning any time soon.

“It doesn’t look good,” Shanahan said. Carriker was still on crutches as he left the locker room and headed to the team bus.

Orakpo dressed and hurriedly left the locker room with his belongings and dress shirt in hand and his shoulder wrapped in bandages. He said he was on his way to be examined by James Andrews, the physician who operated on him in the offseason.

“It just ripped on me, man,” Orakpo said. “Same injury as before. It’s just frustrating, man.”

Without Carriker and Orakpo, the Redskins struggled to stop the run and put pressure on Bradford. The Rams, led by backup Daryl Richardson, racked up 151 rushing yards on 27 carries. Bradford had a strong outing, completing 26 of 35 pass attempts for 310 yards and three touchdowns. He connected at will with Amendola, targeting the 5-foot-11, 188-pound third-year pro 16 times. Amendola caught 15 of those passes for 160 yards and a touchdown to lead all receivers.

Wilson was hurt in the third quarter after running down Richardson and knocking him out of bounds with a flying tackle at the Washington 6-yard line to prevent a touchdown on a 53-yard run. He left the game and never returned.

Despite the struggles and injuries, the defense managed to give its team a chance to win or tie the game. With the Rams trying to run out the clock with 2 minutes 50 seconds left to go, Fletcher forced Richardson to fumble, and cornerback DeAngelo Hall recovered at the Redskins’ 37-yard line. The offense reached the St. Louis 36-yard line before receiver Josh Morgan’s unsportsmanlike conduct penalty backed them up to the 44, where kicker Billy Cundiff attempted and missed a 62-yard field goal on fourth and 16.

“It’s tough,” Hall said. “Wins are hard to get in this league. . . . We had a shot, but we can’t blame it on one particular play or one particular person. There were a lot of plays to be made throughout that game, and their team made more than we did.”