Everyone knows the offensive line is the biggest concern about this otherwise Super Bowl-ready Seahawks team, so it’s no surprise to hear Tom Cable say we are a long way from knowing how that unit is going to shape up.

After Day 4 of camp on Tuesday, the assistant head coach said he was pleasantly surprised at the retention of the spring lessons by the entire unit. But he also made it clear they are just getting going and there is a ton of work to be done as they look for new starters at all five positions.

While the group might be a little ahead of the typical learning curve, it is behind physically — due to injuries to projected tackles Garry Gilliam and J’Marcus Webb.

Cable said Gilliam, coming back from a cyst in his knee, is on a “pitch count” as he makes the move back to left tackle from the right side.

Cable admitted Gilliam is the only option to replace Russell Okung.

“You have the opportunity to draft a left (tackle) if there’s one there. If he’s not, then you use the guys on your football team,” Cable said. “So (Gilliam is) the right answer for us, based on his experience last year and his athleticism.”

That lukewarm endorsement basically matches the thoughts of all of the fans who hoped the Hawks would address the position in free agency or the draft.

But, at least Cable has some confidence that Gilliam can make the switch. He doesn’t yet know what to think of Webb, who missed most of the offseason work with a calf injury. Asked what he has seen out of Webb so far, Cable said, “A guy that looks like he didn’t do hardly anything in the spring.”

Cable said Webb and fellow veteran signee Bradley Sowell (working behind Gilliam) need to adapt to the way the Seahawks play.

“Our system and tempo of play is different,” Cable said. “They’ve been at one extreme; we’re at the other end. So, (they need) to learn to play this fast and aggressive and all that.”

While those guys are new, even the holdovers — Gilliam, Justin Britt, Mark Glowinski — are moving to new positions.

Cable had not been able to learn much in the first four days, and he won’t until the unit plays a couple of preseason games.

“I just like how they’re working,” he said. “We have a lot of work to do, but they’re really doing it. And every day they’re doing something a little bit better, which is cool. So we just keep grinding.”