SEATTLE -- When the 2016 NFL schedule was announced, a Week 3 visit from their downtrodden division rivals appeared to be the least of the Seahawks' concerns in the opening month of the season.

But after scoring a total of 15 points through a 1-1 start, Seattle (1-1) is admittedly searching for answers as to how to fix its suddenly inept offense ahead of Sunday's 4:05 p.m. ET game against the San Francisco 49ers (1-1) at CenturyLink Field.

At the heart of the problem is an offensive line that has only one starter returning at the same spot from the group that helped the Seahawks average 28 points in the final eight games of last season. The overhauled offensive line contributed to quarterback Russell Wilson suffering an ankle injury against Miami in the season opener, and last week the playbook was of the rollouts and zone-reads that have made him so dangerous through his first three NFL seasons.

The Seahawks' lone touchdown came on a late fourth-quarter drive to avoid a massive home upset against the Dolphins, and coach Pete Carroll admitted he is concerned about everything from the line to the imbalance between the running and passing games to the inability to convert on third down (31 percent).

"I never could have thought that we would go the first couple weeks and not score but one touchdown," Carroll said. "I'm just surprised at that. We're better than that."

Wilson insists the offense is "not far off at all," and part of the tonic could be the San Francisco defense, which surrendered 46 points at Carolina last week after pitching a shutout at home against St. Louis in the season opener.

What Seattle still appears to have is a suffocating defense that ranks first in points allowed (9.5 per game) and total yards allowed (248.5) while ranking third (64.0 against the rush) and fourth (184.5) against the pass. Seattle dominated the series last season, winning the two matchups by a combined score of 49-16. And while 49ers coach Chip Kelly's scheme is new to San Francisco, the Seahawks showed they can handle the up-tempo style in a 24-14 victory at Philadelphia in 2014.

"Yeah, we have looked at it, but I don't know how relevant it is," Kelly said. "It's obviously different personnel here, different scheme here in terms of who we are. There's a lot of the same faces there which is one of the reasons they're such a good defense. But we look at everything. So we've probably got 10 or 15 games that we looked at in terms of preparing for Seattle. But I don't know how relevant that matchup was in terms of what we're going to do on Sunday."

The 49ers have averaged 27.5 points through two games, but the passing game ranks just 28th and Kelly has acknowledged that quarterback Blaine Gabbert has left some big plays on the table. At the same time, the team's offensive personnel is still adjusting to the scheme change and Kelly said part of the struggles are also due to poorly-run routes and some protection issues.

"Sometimes it's not the quarterback's fault. It's a combination of everything," Kelly said. "There's a lot that's involved in all of that and I think being good in the passing game on the offensive side of the ball takes all 11 guys."

Offensive coordinator Curtis Modkins said the 49ers have to "get back to basics," and Kelly debunked the notion that the 49ers are always going to run an up-tempo attack.

"That's a misconception we talk about all the time," Kelly said. "We don't try to operate at a very quick pace, and don't try to run more plays than other people run. Just trying to take advantage of what the defense is."

The Seahawks limited running back Carlos Hyde to 40 yards on 11 carries in the first meeting, and a Hyde-less 49ers offense to 61 yards on 15 carries in the rematch. Getting the running game untracked early and keeping Gabbert out of dangerous down-and-distance situations in a tough road environment is critical.

"The Seahawks' secondary is probably the best in the league," Kelly said. "They've got three perennial Pro Bowl players (cornerback Richard Sherman and safeties Kam Chancellor and Earl Thomas). They've got a scheme that those guys have been in for a long time.

"You've got (defensive ends Michael Bennett and Cliff Avril) in that group in the front. You've got two of the best inside linebackers (K.J. Wright and Bobby Wagner). ... So they've got playmakers at every level. There's not a lot of inexperience when you're going against this group."

The 49ers' defense doesn't boast nearly the same crop of household names, and San Francisco struggled to stop the run or the pass in Carolina after its Week 1 stomping of the Rams. Seattle desperately wants to get its ground game going to ease the burden on Wilson and the pass blocking, but the availability of Thomas Rawls (leg contusion) might not be known until game day, which could leave the brunt of the work again to Christine Michael, who is averaging 5.0 yards per carry but also had a game-ending fumble against the Rams.

Wide receivers Doug Baldwin and Tyler Lockett are also recovering from knee injuries in the physical clash against the Rams, and rookie running back C.J. Prosise is also trying to return from a broken bone in a wrist that sidelined him last week.

On the positive front, tight end Jimmy Graham had three receptions last week as he continues to work closer to full strength after knee surgery. His presence could help thwart the pass rush and help Seattle improve on numbers like converting on just 4 of 13 third-down opportunities last week, including only one of greater than six yards.

"That's still the key, and converting and creating a new set of downs and all that is crucial," Carroll said.