SEATTLE >> Bo Nix became Boo Nix. He was not the Brees Knees.

None of this was particularly surprising given the time and place. Rookie quarterbacks are now 4-15 at Lumen Field. And in his debut, Nix looked spooked and was too often off target before providing hope with a nervy fourth-quarter drive that made the final score more palatable.

It was unsettling but predictable and understandable.

What was not was Sean Payton’s performance. As long as Payton works in Denver, he will be shadow-boxing his championship past. It will be used to judge him.

And Sunday Payton wasn’t good enough, making too many head-scratching decisions than acceptable for someone with his pedigree.

His resume hints of an offensive genius, and the Broncos delivered seven three-and-out drives. They were 5 for 18 on third down. They scored nine points on three red zone trips.

Sunday represented Payton’s 276th game as a head coach. It was the first for Seattle’s Mike Macdonald.

So why were the Seahawks more efficient, more opportunistic and more disciplined? Why were they able to make halftime adjustments, something Payton explained as overrated last season? How did Seattle offensive coordinator Ryan Grubb figure out between bites of fruit and sips of Gatorade to feed the ball to running back Kenneth Walker III?

This is the clarity the Broncos require from Payton. He needed to win the chessboard. He has to be held to a higher standard. On a team speckled with young players and one superstar (cornerback Pat Surtain II), the boss is the most accomplished and highest-paid employee. He cannot have a bad day.

There were plenty of fingerprints on this loss, but Payton deserves the most blame.

“I have to be better,” Payton admitted.

Why?

“Any time you have a plan like that and you don’t execute, you don’t run the ball as well, then you’ve got to look at why,” said Payton, whose record fell to 28-12 against rookie head coaches. “That’s why.”

The game gave off CU-Nebraska vibes with the offensive imbalance. With the Buffs it is expected because there is no evidence that coach Deion Sanders values winning over his son’s statistics.

Payton boasts 169 NFL victories and a Super Bowl ring. He knows better. Nix dropped back 44 times, threw 42 times and was sacked twice. The Broncos ran 25 times for 99 yards. That, though, is deceiving. Nix scrambled five times for 35 yards. So everyone else produced 60 yards on 24 carries.

That is 2.5 yards per carry for those who hate math. It eloquently explains why Nix averaged 3.29 yards per passing attempt. And he got hot late to get there. Deep into the second half, he threatened to break Ben Roethlisberger’s record of 2.68.

When the entire game plan requires protecting Nix, putting him in position to succeed, the Broncos not only could not run but abandoned it. Broncos players not named Nix ran the ball seven times in the second half. Seven!

We are not in the meetings or film sessions. But in the NFL, report cards are based on Sunday’s public exam, and this one is an F.

“There’s always that balance. But it’s hard to keep doing it. We are going to look at the tape, and us, as coaches, have to evaluate the run plan and why it wasn’t effective,” Payton said. “It’s going to be hard to play quarterback period if that’s all we can do running the ball.”

Payton struck the right tone about Nix. He defended him, which was appropriate but mildly surprising given his performance. He fell on his sword, but not before swinging it a few times at the offensive line and skill players.

“Bo gave us a chance. Our protection was average at best. … Our rushing yards were not nearly good enough,” Payton said. “At one point in the game, I went to the bench and talked to the receivers and said, ‘Let’s go. Let’s help this guy.’”

Nix is the future. He needs props, not drops. The problem with this strategy is one I broached in the spring: Who are the playmakers? Courtland Sutton caught four passes on 12 targets. Nix finished 2 of 12 on passes over 10 yards with two interceptions. Payton must fight the gravitational pull to throw the ball when receivers don’t get consistent separation, as was the case Sunday.

Payton has never relied on a rookie quarterback, beyond starting Ian Book once because of COVID in 2021.

As much as we talk about Nix’s development, Payton has to evolve with him. He has to design a better ground attack. Heck, maybe putting Nix under center more, giving the running back more options than the half field created by shotgun handoffs. As center Luke Wattenberg said, “We definitely have to be better on first and second down. We have to run the ball, for sure. That’s gotta be our identity.”

Maybe the Broncos just aren’t good enough. That’s not yet clear. But one thing is certain: Payton can’t call 44 passes and expect to receive anything but a failing grade.