SEATTLE (AP) — Kenneth Walker III and the rest of the Kansas City Chiefs stumbled Sunday night against the Seattle Seahawks.

Walker, who came into the matchup against his former team with an NFL-leading 665 yards rushing, was held to 36 yards on 14 carries, with four receptions for 21 yards in a 20-3 loss where the Seahawks dominated in nearly every phase of the game.

Walker played the first four seasons for the Seahawks and was making his first start back in Seattle after signing a four-year, $43 million contract with the Chiefs in the offseason.

Walker was the Super Bowl MVP this past February after rushing for 135 yards in Seattle’s 29-13 win over the New England Patriots. But salary-cap considerations led Seattle to let Walker leave, much to the chagrin of the fanbase as the Seahawks' running game has struggled while Walker has gotten off to a career-best start with the Chiefs.

Walker’s outstanding start to the season played a crucial part in the Chiefs' 5-0 record coming into Sunday, as he averaged a league-best 133 yards per game and 6.3 yards per attempt. But Walker had no room to run against the Seahawks' defense, which came into the game giving up just 237.3 yards per game, lowest in the NFL.

On Sunday, Walker averaged 2.6 yards per rush.

“We know what type of running back was coming in here, but we don’t allow people to run through our defense,” Seahawks linebacker Ernest Jones IV said.

Walker gained just eight rushing yards in the second half, and his longest run went for seven yards. After the game he didn't speak to the media.

“We have to help him,” quarterback Patrick Mahomes said. “I think that’s the biggest thing is when they put so many eggs in that basket of stopping the run game, we have to play the play-action game and the movement game to be able to throw the ball. If we’re not proving that, they’re going to continue to put those guys up at the line of scrimmage, and that’s hard for the run game.”

While Walker struggled, he was far from the only issue for Kansas City. The Chiefs came in with a league-high 414 yards per game average, and the Seahawks held them to 213 total yards.

Mahomes passed for a season-low 165 yards while going 19 for 33, with one interception.

“All three phases struggled,” coach Andy Reid said. “So we’ve got to do better, and that’s my responsibility. I take full responsibility for this. We’ve got to play better as a team. A tough place to play, but this is all part of it. They’re a good football team, and they played well. My hat goes off to them.”

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