CHARLOTTE, N.C. – Though the Vikings had weathered a few injuries on the offensive line during a 10-2 start, they hadn't experienced anything that put them in the same straits they were in for much of 2016, when myriad offensive line injuries contributed to their 3-8 finish after a 5-0 start.

Sunday's game against the Panthers, though, brought concerns about the team's offensive line health to the forefront once again. The Vikings, who had already ruled out right tackle Mike Remmers because of a low back injury, deactivated center Pat Elflein for the game because of a shoulder injury that limited him in practice all week. Then, left tackle Riley Reiff limped off in the third quarter because of a left ankle injury and missed the rest of the game.

Reiff, who was carted to the locker room, was wearing a walking boot in the locker room after the game. He declined to comment, and when Vikings coach Mike Zimmer was asked about his level of concern over Reiff's ankle injury, Zimmer said, "I don't know."

The injuries left the Vikings with only two of their five regular starters on the offensive line, and after Reiff left, only one starter — right guard Joe Berger — was playing his normal position. The Vikings ended the game with Rashod Hill at left tackle, rookie Danny Isidora at left guard, Nick Easton at center, Berger at right guard and Jeremiah Sirles at right tackle.

"I think [offensive line coach] Tony Sparano does a great job of shuffling those guys around in practice," quarterback Case Keenum said. "Heck, I got a lot of snaps with Nick Easton in the preseason, as far as being at center. He has played the position, too, for a long time. You move them around and do lots of different things. It takes some adjustments, but I think communications-wise, they do a great job."

Linebacker Emmanuel Lamur, who left because of a foot injury, was wearing a walking boot and using crutches as he exited the locker room.

Red-zone struggles return

After going 12-for-15 in the red zone in the four games following their bye week, the Vikings reverted to the struggles they had finishing drives in the first half of the season.

They were only 1-for-4 inside the 20-yard line against the Panthers, with Kai Forbath hitting three field goals on drives that didn't result in touchdowns.

"I missed a throw after Andrew Sendejo's interception [in the fourth quarter]," Keenum said. "You have to score a touchdown there. When the defense comes up big after we score, and pull it within three, I wanted that one bad, and I know all of the guys did, too. Coming away with a field goal there, that was tough."

Thielen cashes in

Wide receiver Adam Thielen scored his fourth touchdown of the season when he took a crossing route from Keenum 52 yards for a fourth-quarter score.

That gave Thielen six catches in the game and 80 this season, which triggered an escalator clause in his base salary of $2.85 million for the 2018 season. He'd already put himself in line to earn an extra $500,000 for next season by catching 70 passes, then earned another $250,000 when he hit 80. If Thielen catches another 10 passes in the Vikings' final three games to finish with 90, he'd wind up with a $1 million escalator clause for 2018.

The former undrafted free agent from Detroit Lakes, Minn., and Minnesota State Mankato signed a four-year extension with the team in March.