Kansas City, Mo. ? For five high-flying years, they were planets and he was their sun.

From the time Kansas City acquired him in 2001 until about 2 o’clock last Sunday afternoon when he went feet first into an ill-fated hook slide, ironman Trent Green never missed a start. He hardly missed a snap.

Snugly protected by all-star blockers, he threw passes to Pro Bowl tight end Tony Gonzalez and handed off to Pro Bowl running backs Priest Holmes and Larry Johnson.

Many NFL fans were unaware of how good they were because of how bad the defense was. But even though they never got past the first round of the playoffs, they were just about the best. Green and his Chiefs the past five years had more yards and more touchdowns than any other team in the league.

He became one of the few men in NFL history to pass for 4,000 yards in three consecutive seasons.

But now, for the first time in 82 games, somebody else will be quarterbacking Kansas City. When the Chiefs take the field in Denver on Sunday, their leader will be recuperating from a severe concussion caused when a hit from a Cincinnati lineman slammed his head violently onto the turf and knocked him unconscious.

In his place will be Damon Huard. Until last week when he rushed onto the field as Green was rushed to the hospital, Huard had not completed an NFL pass since Christmas Eve of 2000.

Kansas city quarterback Damon Huard passes in a preseason contest. Huard will be the first quarterback besides Trent Green to start for the Chiefs since 2000.

“It’s been a while, but I’ve been in this role before,” Huard said. “I’ll just step out there and try to pick up where Trent left off. I’ve got a great group of guys around me, future hall-of-famers. We should be good to go by Sunday.”

It’s unsure how long Green will be out. After the Denver game, the Chiefs get an early season bye that could work in their favor by giving him another week to heal.

In the meantime, if Huard goes down, Brodie Croyle will come into the game. He’s a rookie who played little in the preseason and didn’t look very impressive when he did.

All week long the Chiefs have tried to put up a brave front, adopting a business-as-usual approach to an unfamiliar and unsettling scene. As they point out, Huard is not new to the offense. He was the Chiefs’ No. 3 quarterback for two years before ascending to No. 2 when Todd Collins left via free agency.

“As a backup, you’ve always got to be ready,” he said. “You always know your number could be called, any Sunday, any day of the week. That’s your job.”

As a starter in Miami in 1999 and 2000, he was 5-1. And the Chiefs did move the ball when he came in late in the third quarter and went 12-for-20 for 140 yards and a nine-yard TD toss to Gonzalez.

Nevertheless, the Chiefs will doubtlessly tone down their attack from what it might have been with Green under center.

“We’ll find out Sunday,” said coach Herm Edwards. “I don’t want to reveal that right now. I don’t think that’s fair to us. I don’t want to give Denver any more of an edge. They’ve already got one playing at home.”

One thing Huard will have to do is not think about the sight of Green unconscious and helpless on the turf last week.

“You can’t think about it. If you do, you’re going to get hurt,” he said. “You have to put it behind you and play the game.”

The game was delayed almost 12 minutes while Green was strapped to a gurney and carefully wheeled away.

“I’ve never experienced or seen that in all my years in football,” Huard said. “But it’s encouraging to know he’s back on his feet, smiling and talking. But it was scary, man.”