SEATTLE -- The competitive aspect of the Sunday night contest was all but over with the first play of the second half, when Seattle wide receiver Tyler Lockett sped around right end for a 75-yard touchdown run that gave the Seahawks a three-score lead over the Carolina Panthers.

The Seahawks were left to hope that a fractured lower left leg sustained by safety Earl Thomas early in the second quarter won't end up as the evening's more important development.

Seattle hammered the Panthers 40-7 in a matchup of the two teams that combined to earn the NFC's past three bids to the Super Bowl.

Seahawks running back Thomas Rawls rushed for 106 yards and two touchdowns, part of Seattle's 240 rushing yards against a Carolina defense that began the night as the NFL's second-best unit against the run, allowing fewer than 80 yards per game.

However, another potential playoff run for the Seahawks (8-3-1) may be imperiled due to the injury to Thomas, a five-time Pro Bowl selection who missed the team's previous game with a hamstring injury.

Thomas collided with teammate Kam Chancellor while breaking up a pass early in the second quarter and was carted off the field. Back in the locker room for an X-ray, Thomas tweeted shortly before halftime, "A lot is running through my mind including retirement."

Chancellor said, "I feel bad, just because I was a part of it. But it's football. Accidents happen. You can't really tell where people are when you're both trying to make a play. But it's really hard to see your brother go down, someone you care about."

Thomas likely will be out at least six weeks, Seahawks coach Pete Carroll said.

The Panthers (4-8) began the night with a different sort of absence. Cam Newton was benched to start the game for a dress code violation. Newton didn't bring a dress shirt or a tie on the road trip, so coach Ron Rivera decided to sit him for one drive.

In his stead, backup Derek Anderson got things off to an inauspicious start.

On the first snap of the game, an Anderson pass into the flat ricocheted off the arms of intended target Mike Tolbert and into the hands of Seattle linebacker Mike Morgan, who returned the interception to the Carolina 8-yard line. Seattle's ensuing possession resulted in a 23-yard field goal by Steven Hauschka for a 3-0 lead.

"Completely my decision," Rivera said. "The decision was made because I treat them all the same. It was gonna be one series. I didn't anticipate the series lasting one play."

Tolbert, meanwhile, didn't have much to add.

"I've got nothing to say, because what I've got to say wouldn't be good," the fullback said.

Seattle scored again on its next trip, too, when Rawls capped a 92-yard drive with an 8-yard touchdown scamper to make it 10-0.

The teams exchanged long touchdowns early in the second quarter, with Carolina converting a 55-yard bomb from Newton to Ted Ginn Jr., on a third-and-17 and Seattle responding shortly thereafter with a 45-yard run by Rawls, his second score of the first half.

Rawls left the game later in the half and entered the NFL's concussion protocol, but the second-year running back returned to action during the second half and continued doing damage to the Panthers' defense.

Both teams also endured major defensive losses during the second quarter with Carolina defensive end Charles Johnson leaving with a hamstring injury and Thomas carted off.

Seattle tacked on two more field goals in the final two minutes to make it a 23-7 game at halftime.

The Seahawks received the second-half kickoff, too, and wasted little time adding to their edge. After a touchback, Lockett took a handoff on Seattle's first snap, darted outside, tiptoed past a pair of Carolina defenders and was off to the races for a touchdown.

Seattle put the exclamation point on its dominant victory early in the fourth quarter with a 1-yard toss from Russell Wilson to Jimmy Graham that stretched the lead to 30 points. Carolina had marched into the red zone on its previous possession, but a failed attempt to convert on fourth down turned the ball back over to the Seahawks.

Seattle's offense tallied a season-high 534 yards of total offense, including 277 yards through the air from Wilson on 26-of-36 passing. He threw one TD pass and was intercepted once.

Newton finished the night 14 of 32 through the air for 182 yards with one touchdown, and Jonathan Stewart led Carolina in rushing with 50 yards on 11 carries. The visitors finished with only 271 total yards.

The Panthers are three games behind NFC South co-leaders Atlanta and Tampa Bay, while Seattle maintained its three-game lead over Arizona in the NFC West with four regular-season games to go.

NOTES: Four defensive starters returned to action for Seattle after missing the the previous game against Tampa Bay with various injuries: DE Michael Bennett, LB Michael Morgan, CB DeShawn Shead and S Earl Thomas. ... Former Seahawks WR Ricardo Lockette, who retired after a neck injury sustained last season in a game at Dallas, raised Seattle's 12th Man flag before the game. ... Carolina LB Luke Kuechly missed his third consecutive game due to a concussion. ... QB Derek Anderson made his second start of the season for Carolina. He was also under center for the Panthers' 17-14 loss to Tampa Bay on Oct. 10 when Cam Newton was sidelined due to a concussion. ... Seahawks LT George Fant left the game with an injury early in the second quarter and was replaced by fellow rookie Rees Odhiambo.