Garry Gilliam (79) has won back his old spot at right tackle. / Drew McKenzie, Sportspress Northwest

Our long regional nightmare is over — the Seahawks’ 2016 offensive line, a rolling mystery seemingly without end, is resolved.

Garry Gilliam will start at right tackle, as he did a year ago, newcomer Bradley Sowell will start at left tackle, while J’Marcus Webb, the Seahawks’ most expensive purchase in free agency, will watch quietly from the sidelines.

Coach Pete Carroll said as much Monday after the first practice of the regular season, which commences in earnest with hostilities Sunday at the Clink against the Miami Dolphins.

So the Twelves can now fret about something less critical, like climate change.

“We told you it was going to take all camp to do it,” Carroll said. “We did take all camp and figured it out. (We) feel good about Garry. The continuity from last year helps.”

In spring, the Seahawks proposed to put players new to their positions in all five line spots, raising eyebrows around the NFL. But carrying one guy over spoils that narrative.

The Seahawks can still be heckled for spending less on O-line salaries than what ex-teammate J.R. Sweezy will make by himself in his first season in Tampa Bay ($9.5 million to $8.6 million). In fact, the Seahawks are dead last in the NFL, more than $30 million behind the Oakland Raiders’ $38 million, and nearly $5 million behind the next cheapest O-line in Chicago.

But by now, most of us know that this is how the Seahawks work — spend big at all other positions and let assistant Tom Cable coach up the big uglies.

This time, the coaches discovered in preseason that Sowell was playing a better left tackle than Gilliam, who was moved to the left pre-camp, and Gilliam was better than Webb.

“Garry’s just getting started — his upside is still out there,” Carroll said. “It gives us great flexibility having J’Marcus play on both sides for us. It’s a competition in progress on both sides.

“Bradley has done a great job at the other side so far. We’ll keep working our guys and making sure we’re doing the right thing with them. But right now, I thought Garry had a good finish to this camp and he’s ready to go.”

The best thing to emerge from the obscure machinations of the line was the middle of it. Third-year C Justin Britt, second-year LG Mark Glowinski and rookie first-round draft choice RG Germain Ifedi were reported stout and smart.

The O-line drama ending — now all they have to do is knock flat DT Ndamukong Suh and DT Aaron Donald in the first two regular-season games — Carroll addressed two other questions on offense.

He semi-sorta gave a quasi-endorsement of Jimmy Graham to start at tight end, or not, and was pleased to add ex-University of Washington stalwart Tani Tupou as a fullback (and backup D-line) on Sunday after cutting him Saturday.

On Graham:

“We’re going one day at a time with the thought that he’s going to play. That’s our thought. We’ll find out how that works out, with no goal in mind . . . I have no expectations that he’s going to play this week. I’m not counting on that happening. I’m just counting on him coming out and having a really good day Wednesday.”

If Graham is out, the Seahawks have two healthy tight ends, veteran Luke Willson and newcomer free agent Brandon Williams from the University of Oregon.

On Tupou:

“He did a great job. He’s made a terrific transition. He can play on both sides of the ball. We are excited to see him go. He’s a big powerful fullback at 280-plus. He didn’t do much (fullback) in college. Asked (coach Chris Petersen) about that. He hadn’t done a lot, but he had done some and it just made sense to him.’’

There’s speculation that Tupou’s time may be short. After the first game, teams are allowed to bring back veterans without having to guarantee any contract money. That means that last season’s fullback starter, Will Tukuafu, cut Saturday, could return and be paid on a weekly basis.

That would allow the Seahawks to put Tupou on the practice squad, a 10-player unit that still has two unfilled spots.

Team captains named

No surprise that QB Russell Wilson was voted by players as offensive captain for the fourth season in a row. And punter Jon Ryan and CB DeShawn Shead were special teams captains. But in a sign that righteous order has returned to the defense, SS Kam Chancellor was back as captain.

Chancellor was captain in 2014, a tribute to his ferocious play and quiet leadership power, but held out for the 2015 season through the first two games. Things were never quite right thereafter.

“I treat them like my brothers, like blood, so it means a lot for them to hold me to a standard like that,” Chancellor said after practice. “That’s kind of one of my things. I want to practice what I preach. I like to tell the guys the right things to do and motivate them and be a living example. I think it’s big for them to announce me as a captain once again.”

Said Carroll: “He’s always been a great leader for us. He’s a great player, as well. The combination of what he brings and what he does on the field is really, really special to us.”