SEATTLE -- The Seahawks fear that running back Chris Carson suffered a season-ending hip injury Sunday, a massive blow as they head into next week's NFC West showdown with the San Francisco 49ers and then the playoffs.

Seattle also will be without left tackle Duane Brown, who's having surgery Monday for a knee injury that has bothered him for much of the season. Coach Pete Carroll said it's not a major surgery and that Brown could be back in a couple of weeks "if we're lucky."

Carson was injured in the second quarter of a 27-13 loss to the Arizona Cardinals in which the Seahawks also lost his backup, C.J. Prosise, to a season-ending broken arm.

Carroll said postgame that Carson was undergoing tests to determine the severity of the hip injury, but that the team's doctors were telling the coach it appears to be season-ending.

The injuries Sunday come two weeks after Rashaad Penny, Seattle's 2018 first-round NFL draft pick and Carson's backup, tore his ACL. Rookie sixth-round pick Travis Homer was the team's No. 4 tailback before Penny went down and is now the Seahawks' only healthy player at that position. Homer had only two carries from scrimmage entering Sunday, when he gained 16 yards on five attempts.

The Seahawks (11-4) will have to reinforce their backfield before next week's game against the 49ers (12-3), which will determine the NFC West champion. Seattle has Xavier Turner on its practice squad and last week worked out former Seahawk Robert Turbin, as well as Alfred Blue, ESPN's Field Yates reported.

"We do kind of like running the football, you know," Carroll said of losing Carson and Brown. "It's a challenge. [General manager John Schneider] has to get working. He has a plan, and he was already preparing for every position that has a fallout wherever we go."

Carson entered Sunday as the NFL's fourth-leading rusher, with a career-high 1,190 yards and seven touchdowns. Assuming his injury is as severe as the team fears, he will have finished two of his first three seasons on injured reserve.

Brown, 34, has been a regular on Seattle's injury reports this season because of his knee, as well as a biceps injury that sidelined him for two games. He missed all three practices last week. Carroll said the knee wasn't showing signs of improving.

"He needs to get his knee fixed," Carroll said. "He tried like crazy to get through it this week and just couldn't. He did everything he could during the week and couldn't get it to quiet down. He just needs to get his knee cleaned up. It's not a major surgery, but the discomfort is [such] that he just can't play."

Jamarco Jones made his first career start at left tackle Sunday with Brown out, even though George Fant is listed as the first backup at both tackle spots. Carroll said that was to keep Fant in his usual role as the oft-used extra tackle in heavy packages, but he indicated the plan might change next week.

Russell Wilson (16-for-31, 169 yards, one touchdown, no interceptions) was sacked five times and took seven official hits while facing constant pressure against Arizona. The Seahawks drove for a touchdown on their first possession, then punted on seven of their next nine, with a lost fumble in between.

Carroll said the Seahawks "had a terrible time today" in terms of pass protection and pointed to that as a reason their wide receivers combined for only three receptions: one apiece for Tyler Lockett (eight targets), David Moore (two targets) and Malik Turner (three targets). DK Metcalf was held without a catch (one target).

"It was really protection-related," Carroll said. "We weren't able to get the ball off. We couldn't get the ball to them. We thought that Patrick [Peterson] did a good job on DK for the most part. ... Russ couldn't do anything about it. It was a really hard day protection-wise."

The Seahawks also played without Mike Iupati at left guard for much of the first half due to a stinger.

They entered the game with three other starters inactive in addition to Brown: cornerback Shaquill Griffin, defensive end Jadeveon Clowney and safety Quandre Diggs. Carroll's comments did not give the impression that Clowney (core) and Griffin (hamstring) were close to being able to play. Diggs suffered a high ankle sprain last week against Carolina.

"Obviously, those guys are tremendous players, but that's no excuse for us to have the performance we had today," tight end Luke Willson said when asked how injuries affected the Seahawks on Sunday. "The bright silver lining is that it's all on the line next week. Every year, we set our goal for the NFC West. I'm sure CenturyLink Field will be rocking for sure next Sunday."

The latest injuries follow two other personnel hits the Seahawks took this week, with wide receiver Josh Gordon's indefinite suspension and defensive tackle Al Woods' four-game ban.

Carroll was asked how the Seahawks will rally, given all the attrition.

"We are going to figure out a way," he said. "We are going to use all of the same tools that we use all the time mentally to make sure we can be disciplined about it and turn the focus on the next challenge. Our guys do a remarkable job of doing that. So people who question their ability to do it can't believe when we do it. We'll try to show you and prove it.

"The 49ers look awesome. They're playing great football. They had a great win last week. It will be as great of a test as we could play. I'm disappointed we didn't go into [the 49ers game] with momentum, but we're going to re-create it here during the week."