Of that, Colts President Bill Polian said Tuesday there is no question.

But while the Colts’ offensive line will look different without the three-time Pro Bowl left tackle, Polian also said something else is equally true:

The Colts are prepared for a future without Glenn.

And that includes an immediate future.

“I’m always disappointed when a player leaves, but it happens,” Polian said. “Injuries happen. Retirements happen. Players leave because of free agency. It’s the nature of the game.

“While I’m disappointed a good player’s leaving, you move on. That’s what you get paid to do.”

Glenn, the Colts’ starting left tackle since 1998, announced his retirement from football on Tuesday, ending several days of media reports and speculation around the issue.

What does a future without Glenn mean? For the short term, it leaves the Colts with no player on the roster who has started a game at left tackle in the NFL.

“Obviously, it’s hard to replace a player of Tarik’s ability, and all the other contributions he made,” said Polian, who said before the Colts report to training camp on Sunday Glenn will be placed on the reserve/retired list, a move that gives the team a roster exemption and a move that is not “irrevocable.”

“He hardly was ever injured, but you prepare for that as a football team – as a staff and an organization,” Polian added. “We have players who are going to have to step in. That’s what happens in the NFL. The unknown comes up and you have to deal with it and we will.”

Signing a left tackle as a free agent is likely not an option, Polian said.

“The Left Tackle Store is closed, unfortunately,” Polian said, laughing. “Besides which, there are no Tarik Glenns available in the Left Tackle Store. They come along once every 10 years.”

The Colts report to training camp at the Rose-Hulman Institute of Technology in Terre Haute, Ind., Sunday. Currently, there are six tackles on the roster:

• Ryan Diem, a seven-year veteran and the starter at right tackle the past four seasons.

• Charlie Johnson, a second-year veteran and the backup to both tackle positions last season.

• Michael Toudouze, a first-year veteran who spent last season the Colts’ practice squad.

• Dan Federkeil, a second-year veteran who spent the last half of last season on the Colts’ active roster.

• Tony Ugoh, a rookie second-round draft selection from Arkansas.

• Joe Lobdell, a rookie free-agent from Northern Iowa.

Jake Scott, the Colts’ starting right guard the past two and a half seasons, started two games at right tackle in 2005.

“We have a lot of good players on the offensive line,” Polian said. “One of the things that we pride ourselves on is that virtually any player on the offensive line can play any position.”

The Colts selected Ugoh this past off-season with the idea that he has the ability to be a starting NFL left tackle, but the original idea was to develop Ugoh slowly with Glenn remaining the starter.

“If you remember, we said at the time, ‘We have Tarik Glenn – we’ve had him for 10 years,’’’ Polian said. “Here was an opportunity to get a player (Ugoh) who had similar skills and similar temperament – similar physical qualities.

“That was one you couldn’t pass up, because the Tarik Glenns of the world are rare.”

Glenn said after conversations with Dungy, Colts offensive line coach Howard Mudd and Polian, he said feels sure the transition will be a successful one.

“They’re more than confident, and I’m more than confident, because I know the way our system works guys take care of one another,” Glenn said. “It’s going to force some people to grow up. It’s going to force some people to transition out of being dependent upon and actually be the person people depend on. I think the transition is fitting for the time.

“I really believe in Charlie. I’ve always thought he was a really good player, a talented player. He’s smart. He’s athletic. He’s competitive. He’ll be able to do the job.

Glenn worked extensively with Ugoh during the Colts’ summer-school sessions and during the off-season conditioning program.

“Tony, obviously they thought really high of him when they drafted him, so I’m sure there’s enough talent in the (offensive line meeting) room to make it happen,” Glenn said. “I just think it’s going to take a lot of leadership and patience in the offense for that to develop.

Glenn, one of the Colts’ most durable, reliable players in recent seasons, started every regular- and post-season game at the position last season, and during his career, he missed just six games.

That was in 2003, when he missed six games with a knee injury.

Since then, he started 48 of 48 regular-season games, and in the nine-season career of seven-time Pro Bowl quarterback Peyton Manning, those six games in 2003 are the only games in which he has played without Glenn protecting his “blind” side.

“That’s something I think is going to be real hard for everybody,” Glenn said. “For the past 10 years, I’ve been consistent and I’ve been there. After talking to some of my teammates about that, it’s like, ‘Who knows what it’s like to play without Marvin Harrison, Peyton Manning or Tarik Glenn or Jeff Saturday?’ Those guys don’t miss games. They play all the time. They don’t get hurt. So, there is an unknown.”

“The cohesiveness is what I’m sure guys are concerned about – just things running as smooth as it has in the past. But we have so many smart guys on the line. They really understand how things materialize and they have the football IQ necessary to play the position. I’m really confident in it.”

Under Mudd, the line long has had a reputation as one of the NFL’s best units, and also one of the most versatile. Since Mudd joined the Colts in 1998, the Colts often have started inexperienced low-drafted players along the line with little or no dropoff in offensive production.

Through the past 10 years, one of the constants has been Glenn, but even with his absence, Polian said the pieces are in place for a solid line.

“Howard will juggle the pieces and use his magic stirring spoon and come up with the right combination, as he always does,” Polian said. “Howard will sit down at training camp. He’ll mix and match and work different combinations and a couple of days before we play New Orleans (in the season opener), I’m sure he’ll let us know which combination he thinks is best.

“Right now, it’s a question of working through all the various permutations and we’ll come out with the best five.”

Glenn, for his part, said he believes no matter who takes his place, he is “excited to see how it’s all going to work out.”

“I want it to be successful,” Glenn said. “I want it to be better than it was when I was in there. I love those guys and I hope the best for them.”