INDIANAPOLIS – Here are our observations from Day 1 of Colts training camp, which opened Sunday at Lucas Oil Stadium:

>> Line dance

It might seem as though swapping the starting right and left guards would be considered a minor change, especially seeing how it was merely the first day of training camp.

But don’t overlook the gravity of the Colts’ moving — at least for now — Joe Haeg to left guard and Jack Mewhort to the right side. It was just the latest in a long-running series of moves on the Colts’ offensive line, a unit coaches expect to finally come together in 2017 after years of tinkering and shortcomings.

Haeg, the second-year player drafted in the fifth round last year, started four games at right guard and spent most of the team’s offseason practices working there. But coaches must of seen something during film study that indicates this lineup could yield better results.

What might that have been?

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For one, it arguably gives the Colts a better chance of dealing with defensive techniques that opponents might deploy, like stunts and twists from linemen. That was an area where the Colts’ young linemen struggled most in 2016, but moving Mewhort could give them a savvier veteran alongside right tackle Le’Raven Clark. (Clark hasn’t been named the starter but was once again with the first offense on Sunday.)

“At the end of the day, we’re trying to find the best five cemented in there and keep them in there to have some continuity,” coach Chuck Pagano said.

You have and will continue to hear the term “communication” when the Colts talk about the areas where they are seeking improvement on the offensive line. This is another nod to that reality.

And there will be other oddities on the line in the coming days and weeks. With free-agent signee Brian Schwenke still sidelined with a foot injury, the Colts lack a viable backup center. That’s why Mewhort and Haeg will get looks at center from time to time, possibly giving the Colts some insurance behind 2016 first-round pick Ryan Kelly.

>> QB struggles

It’s not uncommon for an offense to be out of sync on the first day of training camp, but it’s hard not to imagine that much of what we saw on Sunday — when the quarterback unit collectively struggled — had to do with the absence of starter Andrew Luck.

It was more or less a continuation of what we saw throughout the offseason, when the quarterback play from Scott Tolzien, Stephen Morris and Phillip Walker was typically uneven.

Tolzien, who is expected to be the starting quarterback throughout the preseason while Luck’s surgically repaired right shoulder continues to heal, was erratic throughout the day Sunday. For every pass like the impressive deep out he completed to Donte Moncrief late in practice, there were others like the late throw to T.Y. Hilton and deep sideline throw to Phillip Dorsett that were way off the mark.

“It’s never going to be perfect,” Pagano said. “You want to come out here and you want to get better every day. Scott’s grown. Scott’s done a nice job since he’s been here. He made some plays and then there were some not-so-good plays. We’ll take a look at the film and make the corrections. We have a long way to go. He’s a tireless worker. He’s got arm talent.”

Yes, the Colts do have a long way to go. And they’ll have to go it without Luck.

>> Defense gets active

It might have been a byproduct of the quarterback play, but whatever the reason, the Colts’ defense got hands on plenty of footballs Sunday.

There were two interceptions, from cornerback Tevin Mitchel and safety Lee Hightower, but several other passes were either batted down or deflected.

Those are good indications for a unit that has been challenged by General Manager Chris Ballard and others to significantly increase its turnover count. The Colts tied a franchise low with eight interceptions in 2016.

>> Odds, ends

A couple of lineup decisions worth mentioning:

The first-team safeties Sunday were Darius Butler (free safety) and Matthias Farley (strong safety). That position is particularly fluid and things could change. At inside linebacker, the Colts went with Jon Bostic and Antonio Morrison as their two starters. Same principle applies there. Things are very likely to change. Chester Rogers got first crack at the third receiver job, an indication coaches feel confident about his chances of winning that job over Kamar Aiken and Dorsett.

Follow IndyStar Colts Insider Stephen Holder onTwitter andFacebook.