RENTON, Wash. - They were Seattle's two biggest splashes in free agency, one counted on to be the steadying presence on an inexperienced offensive line, the other the downfield threat the Seahawks needed in the pass game.

Sidney Rice has yet to see the field this season because of a labrum injury in his shoulder.

And now Robert Gallery is headed to the sidelines for at least the next month with a groin injury that requires surgery.

Not the news the struggling Seahawks needed, especially coming off a 24-0 loss to Pittsburgh that dropped Seattle to 0-2.

"There's a challenge to everybody on this team right now, myself included, that we have to find ways to improve our performance and we all have to work at it really hard," coach Pete Carroll said. "We all have to fight to find ways to make us better and compete like crazy to do that."

It's the second significant injury for Gallery in the last few weeks, but this one will put him out for the next four to six weeks, according to Carroll. Gallery sprained his right knee in the preseason finale against Oakland and missed Seattle's opener at San Francisco.

This latest injury for Gallery came early in the first quarter on Sunday and was an aggravation of a problem that dates to training camp, Carroll said. Gallery played the entire game on Sunday, and the team only learned of the injury afterward.

It's not expected that Gallery would need to be placed on injured reserve, but his earliest likely return would not be until after the Seahawks' bye in Week 7.

"It has been something that has been bothering him," Carroll said. "He has had a groin issue that we thought, after the couple of weeks with his knee, that would get better. But it actually went the other way because of favoring the other side. He got a little more vulnerable, and he studded it out and played through it. He shouldn't have, but he did, and made it through it. We didn't know about it until after the game."

With Gallery out, Carroll said the Seahawks would first go with Paul McQuistan at guard instead of moving rookie right tackle James Carpenter. When Gallery wasn't able to play against San Francisco, Seattle went with Carpenter at left guard and inserted Breno Giacomini at right tackle.

Carroll did hedge, saying keeping Carpenter at right tackle was the plan as of Monday.

Whatever the solution, Seattle's offense needs improvement. The Seahawks were shutout for the first time in four seasons on Sunday and didn't run a play in Pittsburgh's half of the field until the fourth quarter.

Seattle managed a mere 31 yards rushing, with quarterback Tarvaris Jackson and his 12 yards on three carries the leading ground gainer.

Carroll was affirmative when asked if the offensive woes are more than he expected.

"I thought we would be able to move a lot faster, but we've done what we've had to do and we'll continue to push it," he said.

Injuries are nothing new for Gallery, who has missed chunks of the previous two seasons. He was sidelined for four games last year by a hamstring injury and missed 10 games in 2009 due to lower back and leg injuries.

Rice's return is still undetermined. He practiced part of last week, but not enough to where the Seahawks were ready to see how his torn labrum could handle the pounding of game action. Carroll is optimistic that Rice will be able to play Sunday when the Seahawks host Arizona in their home opener.

Rice played just two preseason games while nursing what was originally called a sore shoulder that has carried over into the first two weeks of the regular season. Carroll confirmed that Rice does have labrum damage, but the Seahawks still aren't sure if Rice can play through the injury.

"That's up to the trainers. They're taking him through a very rigorous program to prove that he is OK. You'd be surprised what they're doing to work with him, and he has to make it through practice and all of that," Carroll said. "We'll wait and see how that goes. We can't count on him until he can make it through the week.

"We'll see how that works out but he's determined, and what he's gone through to get to this point has been pretty rigorous to demonstrate that he's OK and at least go to this next level."