RENTON — The Seattle Seahawks will be without their Beast Mode for a while. But they hope to get him back before the season ends.

Seattle running back Marshawn Lynch underwent successful surgery on his abdominal injury, Seahawks coach Pete Carroll announced Wednesday afternoon at the Virginia Mason Athletic Center. The team hopes its star runner will only miss three or four weeks.

Lynch underwent the procedure Wednesday morning in Philadelphia. He flew to Philadelphia on Monday to meet with Dr. William Meyers, a specialist in core and muscle injuries, after sitting out Sunday’s 29-13 victory over the San Francisco 49ers. Lynch was evaluated Tuesday, which led to the decision to have surgery.

“He had his surgery and he’s going to stay back east for a number of days until it’s time to come back, and we’ll see what happens when he returns,” Carroll said. “The doctor was very optimistic about a quick recovery. That could mean within three or four weeks or something like that. There’s a chance, so we’ll see how everything works out. Other than that everything went really well.”

Carroll said that Lynch was not specifically diagnosed with a sports hernia, but that it was related to that. He did not know the specific definition of either the injury or the surgery,

“The doc got in there, he fixed up a couple things and was really able to tack it down real nice,” Carroll said.

“There was nothing more serious in that the doctor projected (Lynch) could get back pretty quickly,” Carroll added. “They fixed everything that was wrong and the doctor was very optimistic about his return.”

Seahawks cornerback Richard Sherman said he’d been in contact with Lynch.

“We’ve had numerous talks,” Sherman said. “He’s in good spirits. It happens, he obviously knows, playing this game. He’s gotten through nine years or so without having surgery, so he’s kind of surprised by the way it went down. But he’s doing fantastic.”

Lynch, 29, has been Seattle’s workhorse ball carrier since arriving via trade with the Buffalo Bills midway through the 2010 season. He missed only one game the previous five seasons, racking up 5,930 yards on 1,346 carries and scoring 54 touchdowns in 75 games, and he became beloved among Seahawks fans for the bruising running style that earned him the Beast Mode nickname.

But it’s been a different story for Lynch this season. Lynch had already missed two games earlier in the season because of a hamstring injury, meaning he’s already missed three times as many games this season than he did the previous five combined. He’s rushed for 417 yards on 111 carries in seven games, meaning both his yards per game (79.1-59.6) and yards per carry (4.4-3.8) are down from his previous five campaigns.

When asked what the Seahawks would miss most from Lynch’s absence, Carroll talked about Lynch’s ability as a receiver out of the backfield.

“He’s a great receiver as a running back,” Carroll said. “He can do all of that stuff. He’s really good. He can run routes, he can get out of the backfield and he has a great sense for finding areas to get open. We’ve seen him catch a lot of balls and make big plays. When Russell (Wilson, Seattle’s quarterback) starts to move around he’s very instinctive. He’s always brought great attitude and all that.

“Beast Mode, you know. He’s got a nickname, so obviously he’s done something.”

Lynch’s various ailments have opened the door for Thomas Rawls. The undrafted rookie from Central Michigan has been a revelation this season, rushing for 604 yards on 101 carries. That included a 209-yard performance this past Sunday against San Francisco, which was the second-highest single-game total in Seahawks franchise history.

“We’re pretty confident,” an understated Carroll said about moving forward with Rawls. “He’s done very well. He’s been consistent and whenever he’s been given a real good shot he’s come through in a big way. I’m excited for him to have another opportunity to go out, see our guys block for him and see what we can get done again. Not every game is going to be like (Sunday), of course, but he certainly gives us a chance to run the ball like we’d like to, and our hopes are very high that he’s going to do very well.”

Carroll also said the team would rely more on Fred Jackson, who’s been used primarily on third downs. Rawls ended up carrying the ball 30 times last Sunday. Lynch carried the ball 30 or more times only once in his Seahawks career.

“We’ll make sure we don’t overdo it (with Rawls),” Carroll said. “You could see in the first half (against San Francisco), he had 11 carries after about 10 minutes of the game. We had to slow down a little bit and get him in and out of there, so we’ll do that to take care of him. It does call on the other guys, and even Derrick Coleman to help us as well.”

Though Rawls has excelled when handed the ball this season, Carroll suggested Lynch would regain the primary ball-carrying role should he be able to return later this season.

“I would think so,” Carroll said. “Why would we not? We’ll see how much we get a chance to work Thomas and see how (Lynch) returns. We might be able to bring him back on a temporary basis, we’ll just wait and see. Of course he’s the guy we would lean on.”

Injury update

Carroll said he expected both center Patrick Lewis and receiver Doug Baldwin to play Sunday against Pittsburgh. Lewis and Baldwin both left last Sunday’s game against San Francisco with ankle injuries, but they should be able to go this week. Carroll was less optimistic about the chances of linebacker Bruce Irvin (knee) and receiver Paul Richardson (hamstring) playing this week, though he said the decision on both would go right down to game time. Carroll reaffirmed that cornerback Jeremy Lane (arm/knee), who’s been on the physically-unable-to-perform list the entire season, will be activated for Sunday’s game. The Seahawks will have to make a move to fit Lane onto their 53-man roster.

Check out Nick Patterson’s Seattle Sidelines blog at http://www.heraldnet.com/seattlesidelines, and follow him on Twitter at @NickHPatterson.