What’s the plan at left tackle?

Joe Staley is by all accounts a top-five NFL left tackle, the cornerstone of what is suddenly one of the league’s best offensive lines. So when he broke his fibula and was certain to be out for several weeks, everyone knew that GM John Lynch would have to sign a replacement.

But who? Tackles were already in short supply, and San Francisco is not the only team scrambling to find a new starting LT. The Chief’s Eric Fisher is having groin surgery, New England put Isaiah Wynn on the Injured Reserve list, and the Bengals are down to their 3rd or 4th LT, I lost track.

So Lynch struck fast and signed — OT Will Holden? To the practice squad? Yes. That’s it.

Which is basically the same as signing no one. Holden is I’m sure a hard-working guy with a great attitude. He has also been released by the Arizona Cardinals twice in the last two years. The Arizona Cardinals.

The rookie

Sixth-round draft pick Justin Skule filled in at left tackle Sunday, and the team is going to stand pat with him. He’s NFL sized at 6’6”, 315 and played a lot at Vanderbilt against SEC competition. It seems like a smart guy with a great attitude.

But he’s going to be way over his head, and that’s just a fact — no slight to him. There will be rough moments. The good news is, the team will learn very quickly is he’s a keeper or not. He has every opportunity to learn on the job now.

The team didn’t have many options, aside from 31-year old Trent Williams, who will cost a premium pick. (Washington is probably unwilling to deal with Shanahan anyway, after his acrimonious departure.) If Williams was 26, a trade might make sense as Staley winds his career down. But not at 31.

So Staley is teaching Skule this week, and OL coach John Benton will make the best of it. But Shanahan can help with his play-calling, too.

First of all, he’ll probably focus on the running game, as he did Sunday. The Niners racked up 259 rushing yards against a solid Bengals defensive line with their 3-headed UDFA backfield, and they’ll probably stay grounded as long as they don’t fall too far behind the Steelers.

Then comes bye week, a nice break for Skule to study even harder. As Cam Inman revealed, the rookie’s dad is the intelligence boss for the FBI, so we can guess he’s a good learner.

Change in personnel?

A typical coach would run more 12 personnel while his LT is injured, with two tight ends inline to help out. Shanahan has been known to put them both on the same side from time to time, and they could both flank the rookie. Heck, he did some amazing things with 13 personnel (3 tight ends) in Atlanta, with a less talented TE room.

The Niners’ zone-blocking scheme is designed to incorporate double-teams on defensive linemen, and Skule could certainly use the help.

But Shanahan’s massively multiple schemes goes much further, and Lynch has been accumulating a lot of hard-blocking skill players to implement it fully. They can achieve the same hyper-blocking result with 21, 31, 23, or even 11 personnel given this flexibility.

Lynch and Shanahan started the off-season with a rare NFL fullback (Kyle Juszczyk), a great blocking (as well as catching) tight end in Kittle, and a stout backup running back (Jeff Wilson, Jr.).

Then they added several more physical blockers at skill positions: Shanny’s old blocking TE from Atlanta, Levine Toilolo; RB-turned-TE/WR Jalen Hurd; and steamrolling wide receiver Deebo Samuel, who ran over and through Cincinnati’s DBs and linebackers all day long on Sunday.

All of these players can line up inline and help block on runs or in pass protection. Heck, Shanahan ran a play where Marquise Goodwin — 5’10”, 180 pounds — lined up inline as if he was going to run block. That should not have fooled anyone, but it did.

The Goodwin play was an example of how Shanahan can make lemonade out of this bitter lemon. He has perfected the leak play, where a tight end, fullback, RB or wide receiver starts blocking for a few seconds, then slips out for a pass — often uncovered.

On Goodwin’s play, he started blocking to the left with the rest of the line, as if it was just another outside zone run. But it was play action, and he ducked out after a few seconds for what might be Shanahan’s most successful sneaky play — a delayed wheel route after some actual blocking.

The Bengals lost track of Goodwin — who covers run blockers? — and he was 15 yards away from any defender when he caught his 38-yard touchdown pass.

With an ultra-green rookie at left tackle, it will be the most natural thing in the world to have Kittle, or Juice, or Deebo, or Toilolo lined up outside of him. Maybe a couple of them. All of them are gritty, physical blockers that can give Skule some real assistance, double-teaming or chipping linemen.

Hurd can help

After the bye, the team will get Jalen Hurd back from injury, too. Do you know how in fantasy football, there’s that hybrid position labeled W/R/T? Hurd is the living embodiment of that. No one’s sure which of the three he is, which makes him a great weapon for confusing defenses. Who’s responsible for covering him?

All of these effective blockers can also leak out for a 30 or 60 yard gain if you forget about them. Besides leading to big plays, this has an even more crucial advantage — discouraging defenders from over-aggressive pass rushes, especially on play-action passes.

Garoppolo gets rid of the ball as quick as any QB in the league. Just a little hesitation from the linemen will give him a considerable advantage.

So count on Shanahan to bring his skill players in tight, inline - 7, 8 or 9 at a time. I expect him to emphasize the run game with lots of play-action and the occasional leak play until Staley returns.

They’ll probably look for another tackle in the draft, maybe with the first-round pick they didn’t squander on Trent Williams. But in the meantime, it’s good to remember than multiplicity doesn’t just help to score. It’s a great way to weather injuries.

POSTSCRIPT:

I want to bump an excellent point by ChillSargent that I completely forgot about. When Jimmy G. had his glorious run of victories at the end of 2017, he had Zane Beadles playing right tackle for four of those games, and he didn’t even know the system yet. I’ll think he can get through Skule.