What we’ve learned about the Seahawks so far

The time for discerning much about the 2015 Seahawks from the preseason may be just about over.

Seattle’s starters played the first half and one series into the second in Saturday night’s 16-15 win at San Diego.

Most figure to get little work in the final exhibition game Thursday at CenturyLink Field against Oakland, with the focus now turning toward getting ready for the regular-season opener Sept. 13 at St. Louis.

So what have we learned?

1. The offense is a work in progress — but how much of one is the real question.

The San Diego game continued an unspectacular preseason for the No. 1 offense. In three games, the No. 1 offense has had 12 possessions. Those have resulted in four field goals, seven punts and one lost fumble.

Russell Wilson is 17 of 31 passing for 146 yards without a touchdown, while the team has rushed for 132 yards on 34 attempts with the No. 1 offense in the game. In what has been roughly five quarters of action overall, the No. 1 offense has 284 yards on 67 plays, a 4.2-yard average (Seattle averaged 5.88 yards per play last season, a franchise record).

After the San Diego game, in which the No. 1 offense had punts on its first four possessions and then two field goals, coach Pete Carroll said “we’re all a little frustrated with it.’’

But he also quickly added that “I’m not worried about it over the long haul.’’

Carroll correctly pointed out that Marshawn Lynch has gotten just three snaps in the preseason (the first three plays against San Diego) and that the team is not fully game-planning and is still working on developing the offensive line.

The question is what percentage those caveats are contributing to the lackluster performance of the starting offense.

One person who didn’t sound worried is Wilson. He missed a few throws against the Chargers, one time throwing over the head of Jimmy Graham, which Wilson joked is “tough to do.’’

But afterward, he said he thinks the offense will be just fine once the regular season rolls around.

“It really comes down to finishing those drives,’’ Wilson said. “And that’s on me. And we’ll do that. I think everybody else is really on course.’’

2. The line remains the biggest work in progress on the offense.

Carroll was noncommittal after the San Diego game as to whether he had seen enough from the new alignment — featuring Gary Gilliam at right tackle, Drew Nowak at center and Justin Britt at left guard — to stick with it for the regular season. That answer could come at practice Tuesday.

Regardless, the line will remain an area of concern until it proves otherwise. As Carroll noted, the Seahawks “didn’t block anybody’’ on a third-and-one on the first series in which Lynch was held to no gain. And the line was hardly dominant when matched up against San Diego’s reserves on the first series of the third quarter, when Seattle got to the 2 but had to settle for a field goal.

Carroll said it may not be fair to judge the line until it plays regularly with Lynch, which won’t happen until the regular season.

“Twenty Four in the game looks pretty good to me,’’ Carroll said. “When he plays, it looks a little bit better. He’ll help those guys.’’

3. The defense could be more aggressive under new coordinator Kris Richard.

The Seahawks brought a fair amount of designed pressure against the Chargers, including sending cornerback Will Blackmon on a play that resulted in a second-quarter sack of Philip Rivers.

“I think you’re seeing Kris is a little more aggressive than we have been, which I love,’’ Carroll said. “And he is playing to the strengths of the players.’’

Carroll has talked often that this could be the fastest defense he has ever had, especially up front.

“This looks to be a team, maybe more than we have been, to be able to pressure the way we are hitting stuff, and the timing and the speed that our guys can hit it with was apparent against good protection and a quarterback that knows what he’s doing and all that.’’

4. Tyler Lockett will really help the return teams.

This is no news flash, but it’s worth reiterating as Lockett has emerged as the star of the preseason. Seattle has four touchdowns in the preseason. Lockett has scored two on returns — a 103-yard kickoff return against Denver and a 67-yard punt return against the Chargers.

“It’s a great threat that will help us in any situations to come,’’ Carroll said.

5. The Seahawks’ defense still misses safeties Earl Thomas and Kam Chancellor.

If there’s been a flaw with a defense that has largely played well, it has been third downs — Kansas City and San Diego were a combined 11 for 20 on third downs against Seattle’s starters the past two games. Many have come on short passes, and it was easy to think the regular Seattle secondary would have prevented them. The good news is that Thomas is expected to be ready for the regular season, and all the veteran cornerbacks are now healthy.

That leaves only Chancellor, whose holdout — and questions about how and whether it gets resolved — may be the biggest mystery remaining of the preseason.