Coming off one of their best defensive performances of the season as well as their bye week, the 49ers’ defense seemed to get another boost before Sunday’s game. Longtime tormentor Marshawn Lynch wouldn’t play because of an abdomen injury.
Instead of catching a break, however, San Francisco was steamrolled by Lynch’s unheralded understudy, Thomas Rawls. The undrafted rookie finished with 209 rushing yards in his team’s 29-13 win, more than Lynch has gained in a game and a record for a 49ers opponent. The previous high was a 192-yard effort by Atlanta Falcons running back Erric Pegram in 1993.
Jim Tomsula, who coached the 49ers’ defensive line for eight seasons, called the overall effort “lifeless.”
“Defensively, I was not happy with the way we came out,” said Tomsula, whose team has yet to win on the road this year. “ ... We didn’t tackle well. We didn’t (play) the run well. That has to be better.”
The defensive lapse masked a solid outing by quarterback Blaine Gabbert, who had 264 yards and a 98.2 passer rating, and it dropped the 49ers to 3-7 this season. The Seahawks improved to 5-5 and took sole possession of second place in the NFC West.
The 49ers entered the game with new faces at several positions against the Seahawks, but the results were mostly the same, right down to losing a key defensive figure for perhaps the rest of the year.
On the first defensive series, starting defensive lineman Glenn Dorsey collapsed when his knee buckled. Tomsula said the eight-year veteran was being checked for an ACL injury.
In previous seasons, nose tackle Ian Williams and linebacker NaVorro Bowman suffered grisly injuries in Seattle, and both were among the team captains who went out for the ceremonial coin toss before the game.
“There’s something about playing here,” outside linebacker Ahmad Brooks said. “ ... It’s always dark and gloomy. You see guys dropping like flies.”
“Glenn going down early, that really hurt us,” Bowman said. “Rawls wanted to prove himself to the Seattle Seahawks today, so he came out with a chip on his shoulder. We have to play better, we have to tackle better, and if we (did) that, this game would have been a lot different.”
First-round draft pick Arik Armstead (Pleasant Grove High School) mostly filled in for Dorsey and led the team’s defensive linemen with six tackles to go along with a quarterback hit. Asked about Armstead’s efforts, Tomsula said, “There were some ups and downs.”
An example of Armstead’s potential came in the first quarter with the Seahawks facing a third-and-short scenario. Armstead fought off two Seattle offensive linemen and met Rawls in the backfield. But he couldn’t make the tackle, and the Seahawks runner picked up two yards and the first down on a drive that would end with a touchdown.
“I’ve got to turn on the film and learn from it and try to help my team next week,” said Armstead. “The more reps I get, the better feel I have for the game.”
Lynch, who had run for at least 100 yards in six of the last 10 meetings against the 49ers, was listed as questionable for the game. But he had played his team’s previous game with the same designation, and the 49ers said they prepared all week as if the powerful former Cal runner would play.
Instead they got Rawls, a 5-9, 215-pound runner from Central Michigan who was a long shot to make Seattle’s roster when training camp began.
“Marshawn is hard to bring down,” Brooks said. “This guy seemed like he could get up the field a lot quicker.”
Rawls had three carries of 20 yards or more on the afternoon, and he also scored on a 31-yard catch and run in the fourth quarter. But his gaudy total was more the result of a steady workload. He carried the ball 30 times, and the Seahawks had seven drives of seven or more plays. They converted 57 percent of their third-down opportunities and held the ball for 37:39, 15 minutes more than the 49ers.
Rawls’ big outing came on the heels of one of the 49ers’ strongest defensive efforts, one in which they held Falcons running back Devonta Freeman, who entered that game as the league’s leading runner, to 12 yards on 12 carries.
“My hat’s off to him,” linebacker Michael Wilhoite said of Rawls. “I think he ran the ball well. (But) we didn’t do what we were supposed to do. We missed tackles. We weren’t in the right gaps. What you saw against Atlanta was very good team defense. And we didn’t play like that today.”