His coach thinks he will be the best quarterback ever. He has a long way to go.

Los Angeles Chargers head coach Jim Harbaugh was not shy when discussing his expectations for starting quarterback Justin Herbert before the season, opting instead to make a very specific — and very bold — claim.

“Allow me to call my shot, like Babe Ruth pointing his bat over to centerfield. Justin Herbert, when it’s all said and done, when his career comes to an end, I predict he will be known as the greatest, best ever to play the position of quarterback,” Harbaugh said during an appearance on the podcast “The White House with Michael Irvin.”

“When it’s all said and done, and his career is finished, we’re going to look back and say, ‘Yep, that’s the best that ever did it.’”

Harbaugh, in his third season as the Chargers’ head coach, is known for his quarterback acumen, so his words can’t be immediately dismissed. In college, he coached future first-round picks such as Andrew Luck and J.J. McCarthy. And in the NFL, he brought out the best in Alex Smith and Colin Kaepernick.

Herbert, the sixth overall pick in the 2020 NFL draft, has long tantalized analysts because of his supreme physical traits, which include athleticism and a cannon of a right arm. To add fuel to the fire, Harbaugh earlier this year hired a new offensive coordinator, former Miami Dolphins head coach Mike McDaniel, a quarterback guru in his own right who led the Dolphins to great offensive heights for multiple seasons.

So a perfect storm was brewing for Herbert to live up to his head coach’s lofty dreams in Week 1. Instead, in a week when offenses dominated the NFL, Los Angeles fell flat, mustering only two touchdowns in a 26-14 loss to the Arizona Cardinals.

After one report claimed McDaniel was going to explore more of his playbook thanks to Herbert’s physical gifts, the quarterback ended his first start with a pedestrian stat line: 17 of 27 passing for 209 yards, with one touchdown and one interception.

On Sunday, Harbaugh described the performance as sloppy. On Monday, he lamented not having the team more prepared.

“Now in retrospect, wish I would have played our guys a little bit more in the preseason getting those game-like reps,” Harbaugh told reporters after saying the team committed too many “preseason-type” mistakes.

At least in terms of what went wrong, the coach and quarterback are on the same page, as Herbert repeatedly mentioned execution issues Sunday.

“We can’t expect to win like that,” Herbert said. “And we have to do better.”

While Herbert can’t control the opinions of the masses — or even his own coach — he does occupy a strange space in the NFL quarterback ecosystem. Before the season, The Athletic’s Mike Sando polled 50 coaches and executives as part of his annual QB Tiers ranking, and Herbert took the sixth spot.

But Herbert is coming off a season in which he finished only 15th in passer rating. And since 2024, among quarterbacks with a minimum of 500 plays, Herbert is only 17th in adjusted expected points added per play and 20th in success rate, per RBSDM, an advanced analytics site for NFL statistics.

McDaniel was supposed to be the coordinator who could bridge the gap between Herbert’s talent and production — particularly after McDaniel drew up high-scoring offenses for Tua Tagovailoa, a quarterback not nearly as physically gifted as Herbert.

Whatever the Chargers’ issues are, the offense needs to get on track fast, as their schedule is unforgiving. Over the next two months, Los Angeles will face a gauntlet that includes multiple MVPs (Josh Allen, Lamar Jackson), multiple recent Super Bowl winners (Seattle Seahawks, Kansas City Chiefs), and multiple ferocious defenses (Denver Broncos, Houston Texans).

If the Chargers are going to survive such a hellacious stretch, then their quarterback will have to start living up to what his coach (and seemingly most of the NFL) believe he can be.