Kansas City Chiefs defensive assistant Michael Ketchum, left, and guard Herb Taylor (65) step between center Wade Smith and Bernard Pollard (49) during afternoon drills at football training camp last week in River Falls, Wis.

River Falls, Wis. ? It wasn’t always this way. Rivals once cast envious eyes upon Kansas City’s offensive line.

Guards Will Shields and Brian Waters and left tackle Willie Roaf all went to the Pro Bowl in 2004 and ’05. Many thought center Casey Wiegmann should have joined them.

But last season, with everyone but Waters either retired or let go, one of the league’s best offensive lines turned into possibly the worst.

The Chiefs’ 55 sacks allowed were the most in the league. Largely because of poor blocking, harried Kansas City quarterbacks threw 20 interceptions. Until he missed the last eight games with a broken foot, Pro Bowl running back Larry Johnson was getting hit so often in the backfield he hurled his helmet several times in disgust.

The Chiefs would have been derelict if they hadn’t cast off aging, ineffective Chris Terry, John Welbourn, Kyle Turley and Wiegmann.

Now the only starter who’s back at the same position is Waters, a three-time Pro Bowl left guard and nine-year veteran. The new line has bigger guys, but it’s not yet known if they’ll be any better, especially at first. It’s a concern for a team trying to recover from a 4-12 record and a nine-game, season-ending losing streak.

“They’re getting better,” said coach Herm Edwards. “I think what we’re asking them to do fits what they can do.”

After playing guard most of his distinguished college career, rookie Branden Albert, 6-foot-5, 315 pounds, is switching to left tackle, handed the job after being drafted in the first round last spring.

Also new as a starter is center Rudy Niswanger. An exceptionally intelligent man who opted for a professional football career instead of medical school, the 300-pound Niswanger was groomed for the part his first two years. But he but has never been a starter at any position in the NFL.

At right tackle is nine-year veteran Damion McIntosh, a 6-4, 320-pounder who’s unhappy about being switched from left tackle.

The new right guard is Adrian Jones, a five-year veteran, who was claimed off waivers from the New York Jets in December.

Pressure is being applied at many positions from backups. But that’s the line that has taken shape since spring workouts. The group will probably get more playing time in the preseason than starters normally do because coaches want a good look.

“I think we’re progressing as a unit. Remember that we started this process in March,” said McIntosh. “It’s nothing new right now. We’re going into August, so we’ve been doing this for months now.”

McIntosh’s knee is also a worry. He hurt it in the preseason last year and has had it wrapped at times this week.

He also acknowledges he’s more accustomed to the left side.

“I’m working at it. I’m doing OK, been working on it this whole offseason,” he said. “It’s a challenge that was given to me and I’m fine with it. I’m a ballplayer. They want me to do something, I’ll work at it. This is my craft. This is what I’m supposed to do.”

Albert, drafted with the extra first-round pick obtained in the trade that sent Jared Allen to Minnesota, is being asked to master one of the most vital positions on the team on the fly.

“We thought when we drafted him that he would have the ability to play tackle,” said Edwards. “That’s why we drafted him. There was no concern there that he had to be a guard. He was going to be a tackle. We put him out there and he’s going to play left tackle for us.”

In the first week of camp, some of the veteran defensive linemen have seemed to get the best of the rookie who’s long on potential but short on experience.

“He’s going to go through some growing pains, and that’s part of it,” said Edwards. “But the guy has very good feet, is a very good athlete, a smart guy. Very smart and picks up things. He learns something every day.”

Niswanger is exceptionally tall for a center: 6-5. But he’s also more than 60 pounds heavier than Wiegmann, who was ideal for the rollouts Kansas City used to run in the Al Saunders-Dick Vermeil offenses.

He appears fully recovered from a knee injury incurred late last season. But he has almost zero experience as an NFL center.

“I think he’s got a great upside,” Edwards said. “He’s a very smart guy and can get guys lined up. Now, he’s tall and that’s kind of unusual as a center. He’s played the position in college. He needs an opportunity and is doing a good job.”