Nick Canepa grades the Chargers following Sunday’s 35-6 loss to the Jaguars in Jacksonville:

Quarterbacks: F

There was a horrible protection issue on the first play that led to intentional grounding. Justin Herbert’s first sack was of the coverage variety, and so was the second. Just prior to the half, Herbert was hurt on a roughing-the-passer call that really wasn’t. But he returned — yeah, to more pressure. He threw a horrible pick that was returned 43 yards when down 28-6 and was eventually replaced by Trey Lance. Despite his line, it was maybe Herbert’s worst game since he was growing up in Oregon.

Running backs: F

Kimani Vidal, their bell cow as fourth-string back, hurt his knee early in the second quarter, giving way to fifth-string Trayveon Williams and sixth-stringer Amar Johnson. Vidal returned to start the second half, but nowhere to go.

Receivers: F+

Zero degrees of separation all day. Rookie tight end Oronde Gadsden was healthy and available right away. He’s a true find, but receivers may as well have stayed on the school bus. When receptions were few, Keenan Allen made himself known, making a terrific, 30-yard catch as the halftime curtain was closing.

Offensive line: F

With Joe Alt out with an ankle, Trevor Penning, recently acquired in a trade, wasted no time starting over Austin Deculus at left tackle. Herbert was pressured. A lot.

Defensive Line: F

The run defense stunk early and didn’t get better in the first half. Teair Tart made a nice tackle and so did Justin Eboigbe and Jamaree Caldwell, but, really, these guys got their butts kicked all day.

Linebackers: F

Khalil Mack never stopped coming, but, like everyone else, he got blocked a lot. Daiyan Henley had a huge fourth-down whiff they had sniffed out, leading to a touchdown. Troy Dye missed a goal-line tackle. The defense allowed Bhayshul Tuten and Travis Etienne to run like Gale Sayers and Jim Brown. Troy Dye actually made a play.

Secondary: F

Donte Jackson had a terrific second-quarter pick. Derwin James made the first tackle. Elijah Molden had his name called on a bad pass interference call in the end zone and a missed tackle. Tarheeb Still had a bogus PI call that led to the first touchdown. Cam Hart got beaten from Jax to Myrtle Beach on a touchdown.

Special Teams: F-plus

Cameron Dicker The Kicker opened scoring with a 41-yard field goal and then made it 7-6 with a 41-yarder. But special teams this year has been spotty, with basically no threat in the return game.

Coaching: F-

One game out of first place in the AFC West, and Jim Harbaugh coached the most un-Jim Harbaugh game of his career. His team was unprepared in every phase. They stunk against a dead-flat average team. Jax — Jacksonville! — never punted.

Next opportunity — Bye: F

What good will it do? The tackles aren’t coming back. Maybe tailback Omarion Hampton will return, but it’s impossible to see this team winning a meaningful game.