We learned a lot about the Seahawks’ offensive line over the past couple of days — and we’ll learn a little more tonight when the Hawks host the Minnesota Vikings.

On Wednesday, Tom Cable announced that three-fifths of the line is set for the season opener, and Thursday the team announced that one of those three is set for the next four seasons — Justin Britt signing a three-year, $27 million extension.

It’s the only second deal for a Seattle starting lineman since 2012, when the team re-signed Breno Giacomini and extended Max Unger. As everyone knows, those two and the rest of the 2013 Super Bowl line were all gone by 2016 — none of them meriting what the market dictated the Hawks would have to pay.

His first two years, it certainly didn’t look like Britt would buck that trend. But he found a home at center last year and benefitted from the departure of J.R. Sweezy, becoming a technician rather than a Sweezy-style brawler.

“He has been a fantastic leader for us up there,” Pete Carroll said. “He had an excellent (2016) season and (has) played three spots and started at tackle, guard and center now. We really think he is in the best spot for him. I think it’s a recognition and acknowledgement of the player and teammate he has become for us.

“And also the fact that we are able to do it in the offensive line — I think it is important to note.”

Carroll has talked about establishing consistency up front, but it remains to be seen whether any of the other linemen end up deserving second Seattle contracts.

Luke Joeckel is on a prove-it deal and will start at left guard. George Fant, the bizarre UDFA story from 2016, will start at left tackle again and continue to learn on the job; if he works out, the Hawks will have a cheap left tackle for the next three seasons.

“We think that’s a really good combination there at the left side,” Carroll said. “I feel really good about that right there, going into the next game. We are always growing with information, but I see Luke as our starting left guard and I see George as our starting left tackle right now.”

Cable thinks Joeckel and Fant are a good tandem. “We’ve talked a lot about (Joeckel’s) calmness and his experience level and some of the things he’s faced in his own career. Not much different than George in a lot of ways, other than he had a football background. So I think it’s having a great positive effect in regards to their great communication, being able to settle down, keeping them kind of on point.”

Mark Glowinski and Germain Ifedi are the incumbents on the right side, even though they both are switching positions. But both had their struggles in the preseason opener — Glowinski more than Ifedi — and face big challenges from newcomers Oday Aboushi and Ethan Pocic.

“There’s still a big battle going on at the right side, both guard and tackle,” Carroll said.

Cable said, “We just want to make sure the opportunity is there for everybody to compete, get their opportunity on the right side, and then we’ll make that decision. Hopefully sooner rather than later.”

We have said he needs to pick five by the third preseason game so they can play together for a few quarters.

Pocic is going to mix in at right guard this week, too. Part of that might be to get Ifedi more reps at right tackle. Cable said he is disappointed Ifedi missed a few days after being sucker-punched by Frank Clark, and “we’re trying to play catchup a little bit.”

The other part of it is the flexibility the Hawks love in Pocic, who could end up backing up three spots. Aboushi and Rees Odhiambo can play more than one spot, too, which is bad news for Joey Hunt.

“He’s playing the one position at center. He’s a fantastic guy if you need someone to go in on a play,” Cable said of Hunt. “The unfortunate thing is that’s really what his job is — playing center. Where, as you know, most of our guys play a couple spots.”

Cable talked about finding the sixth, seventh and eighth linemen — reminding that the team usually has just seven active. That could mean bad news, too, for UDFA guard Jordan Roos — even though Carroll recently talked him up like he had made the team. It’s certainly possible the team goes with nine linemen, as it did last year when Fant was the UDFA keeper.

The line got off to a typical inconsistent start in the preseason opener vs. the Chargers, and tonight’s game will be a good test against a solid defensive line. It’s the next step in settling on the first five and finding the guys who will prove worthy of playing alongside Britt for a few years.

“I’ve said it before: Very excited about this group,” Cable said. “Hopefully they’ll be able to stay together and play together for a good while.”