Michigan against their longtime hated rival in a season-opening game today at SoFi Stadium filled to overflowing with compelling storylines.

Maybe it’s best to begin with Harbaugh and work backwards.

“Game week, super excited,” he said in the days leading up to his return to the league. “Every day matters, but the games count so there’s an appropriate air around the facility and the building. Team meetings. Let’s go. It’s a big rivalry. It’s felt, for sure. … It’s the opener. It’s a big game. It’s a big week.

Of the many ways the NFL has changed since he last coached the San Francisco 49ers in the 2014 season, he said, “I think I’ve said this a few times, but I didn’t think the NFL could get any bigger, any more exciting than it was a decade ago, but it has. I don’t know how many times more, two, three, 10 (times). When I didn’t think it could get any more popular, it has.”

Of his personal growth during his nine seasons at Michigan, which included a 15-0 record and a national championship last season, he said, “I don’t know. I don’t have that list in front of me. I think I’ve grown. I’m pouring the same amount into it, which is everything. Heart and soul into the job. Love this team. Super happy to have the work to be able to go to every day, have that common goal, part of the team in creating a ball team. I want this to be our favorite ball team we’ve ever been on.

“Every guy. Every man, woman in the organization, when you think about Little League, high school, college, pro, I want this to be their favorite ball team they’ve been on.”

So, you know Harbaugh is fired up for Sunday.

He’s also excited about coaching Herbert, whose 2023 season ended with a broken index finger during the Chargers’ loss Dec. 10 to the Denver Broncos at SoFi Stadium. Herbert also sat out three weeks of training camp because of what the team said was a plantar fascia injury in his right foot.

“Right out of the chute, one of the best leaders I’ve been around,” Harbaugh said of Herbert, who is entering his fifth season in the NFL. “From Day One, he’s a rock. In every way. The hardest worker. A tone setter. Strategist. A performer. A producer. He leads from the front. Tremendous.”

Herbert also is fired up for today, when he’ll have new targets after the departures during the offseason of top wide receivers Keenan Allen and Mike Williams and running back Austin Ekeler. Joshua Palmer, Quentin Johnston and rookie Ladd McConkey will be asked to replace Allen (traded to the Bears) and Williams (cut) and Gus Edwards and J.K. Dobbins will share the duties in place of Ekeler, who left for Washington as a free agent.

So, Herbert was naturally a little bit cautious going into today.

“That’s the tough part of sitting out, you’re not getting the reps with those guys,” he said of his nearly three-week layoff because of his foot injury and the lack of opportunity to connect with his teammates. “They’re all new, the entire offense is new and you’re trying to pick it up as quickly as you can.”

Like Herbert, Bosa also is returning from a training camp injury. He suffered a broken left hand that required surgery during a joint practice with the Rams on Aug. 4, an injury he said is “95%” healed, which is good enough for him to face the Raiders without protective padding.

The one-on-one matchups between the Chargers’ James and the Raiders’ Adams and the Chargers’ Alt and the Raiders’ Crosby are two of the most intriguing individual battles that will highlight an AFC West rivalry game that could be one of the most enticing of Week 1 around the NFL.