By Chris Biderman

Associated Press

SAN JOSE, Calif. (AP) — The Panthers’ offensive line has been devastated by injuries this season, the latest coming with centers Ryan Kalil and Gino Gradkowski being placed on injured reserve Tuesday.

With left tackle Michael Oher out for the year with a concussion and backup right tackle Daryl Williams nursing an injury, the Panthers may have even more problems protecting franchise quarterback Cam Newton on Sunday at Seattle.

Kalil, a five-time Pro Bowl selection, missed three of the past four games before the Panthers placed him on injured reserve with a shoulder issue. It likely forces undrafted rookie Tyler Larsen to start at center against the Seahawks’ top-ranked defense.

“(Kalil’s) one of the best players at his position in the NFL. He might be the best center,” Seahawks coach Pete Carroll said. “So when you lose that caliber of player, you don’t just lose the physical play, you lose the leadership and the smarts and all that.”

Panthers coach Ron Rivera said it’s going to be up to Larsen to help patch together a makeshift offensive line in noisy CenturyLink Field, where Carolina played the past two seasons, including the playoffs in 2014.

“He’s done a nice job for us, he’s handled it very well,” Rivera said. “I’m pretty excited about him getting his opportunity. … I think we’re going to be fine.”

Larsen was signed as an undrafted free agent from Utah State, and has appeared in only three NFL games. He was released from Carolina on Oct. 8 before being brought back to the practice squad. The Panthers promoted him to the active roster Nov. 4.

The Seahawks (7-3-1) have the NFL’s top-ranked scoring defense, allowing 17 points a game. They’ll be looking for revenge after the Panthers ended their season in the 2015 divisional round playoff with a 31-24 decision in Charlotte.

The Panthers elected to stay in the Bay Area this week to practice at San Jose State and cut down on travel time with consecutive games on the West Coast. They’ll prepare for Seattle on the same practice field they used before their loss in Super Bowl 50 to the Denver Broncos at nearby Levi’s Stadium.

Carolina is coming off a defeat to the surging Raiders, 35-32, in a back-and-fourth game in Oakland. The Panthers took a 32-24 lead in the fourth quarter after falling behind 24-7 in the first half. But Oakland scored 10 points inside the final five minutes, dealing the Panthers (4-7) their fourth loss in five road games.

It’s been an unexpectedly turbulent season for Carolina after Newton was honored as the 2015 MVP following a 14-0 start.

The team’s regression can be traced to the slew of injuries along the offensive line. Only one player, left guard Andrew Norwell, is playing the same position where he began the season. Carolina credited good health for playing a role during the successful run to the Super Bowl. It hasn’t lasted in 2016.

“It’s a trickledown effect. It affects everything,” tight end Greg Olsen said. “That’s the nature of football. . . Last year was an anomaly with being relatively healthy throughout the season. It happens throughout the league. It’s just sometimes the luck of the draw.”

Williams didn’t practice Wednesday while he continued to sport a walking boot on his left foot after suffering an ankle injury late in the second quarter against the Raiders. If Williams can’t play, the Panthers will likely have right guard Trai Turner play right tackle, where he hasn’t started since high school.

NOTES: LB Luke Kuechly (concussion), WR Kelvin Benjamin (shoulder), S Kurt Coleman (concussion), DL Ryan Delaire (knee) did not practice Wednesday. … The Panthers announced a $250,000 donation to high school athletic programs in North and South Carolina impacted by flooding and wind damage from Hurricane Matthew. The money is to assist in the replacement or repair of equipment, supplies or athletic infrastructure lost or damaged by the storm.