INDIANAPOLIS -- The Indianapolis Colts never worried about what it was like to not have quarterback Andrew Luck taking snaps during his first 51 regular-season games.

Get sacked. Get hit. Get up. Rub some dirt on it and keep playing.

Repeat over and over again.

Needing the backup quarterback to play was a foreign concept for Indianapolis.

Last year, the Colts found out Luck wasn’t invincible after he missed nine games. Fast-forward to today, and the Colts again are preparing to play without their best player while also trying to stay in the hunt for an AFC playoff spot.

Luck has been ruled out of Thursday's game against the Pittsburgh Steelers because of a concussion. Scott Tolzien will start in his place.

With a concussion bumping Andrew Luck (12) from the lineup, the Colts will be led by Scott Tolzien (16), making his first start in three years. Benny Sieu/USA TODAY Sports

This Colts team is well aware of what happened last season. They went 6-3 without Luck, but still missed the playoffs. And they're hoping they won't have to once again go an extended period of time without their franchise player, who has to clear the concussion protocol before he can play again.

“I think we all learned a lot about ourselves, the entire football team,” coach Chuck Pagano said of last season's stretch without Luck. “I know there are a lot of guys that aren’t here that were on that team. I think having the ability to overcome those circumstances of not having a quarterback for that amount of time, as a football team, you can still win. So having been down that road, we’ve got a bunch of guys in that locker room that went through that, a bunch of coaches. So we’re prepared and obviously ready for the challenge.”

When Luck suffered a lacerated kidney against the Denver Broncos in Week 9 last season, veteran Matt Hasselbeck took over as the full-time starter as the Colts were trying to catch the Houston Texans in the AFC South. Tolzien is taking over the starting role while the Colts are again trying to catch the Texans in the division race.

You don’t have to look too deeply to see the biggest difference between this situation and that of last season: the resumes of Hasselbeck and Tolzien.

Hasselbeck took over for Luck having played in 201 games in his career. Tolzien can’t say the same. While he has had the opportunity to play behind players such as Luck and Aaron Rodgers, the latter while he was in Green Bay, Tolzien has only made six career game appearances. His start against the Steelers will be his first in exactly three years, the last coming while he was with the Packers.

What Tolzien has going for him, according to Hasselbeck, is that -- if last season was any indication -- Colts offensive coordinator Rob Chudzinski will simplify the offense as much as possible so the quarterback won’t have too much on his plate.

Tolzien has also had the opportunity to get some first-team snaps in practice, because Luck has been limited for at least one day a week for most of the season.

“I guess you can say you don’t have all those snaps and that body of work and all that tape and passes thrown, protections checked and all those types of things,” Pagano said about Tolzien. “I guess from that standpoint, but Scott is the guy. Scott has got a ton of ability, and I have all the confidence in the world in this guy. And this organization does, and most importantly, the locker room and the players that are in that locker room have all the confidence.”

The Colts will not be favored Thursday, and rightfully so. But Pagano's demeanor doesn't indicate that. The outcomes haven't always been what he has wished for, but his coaching style includes making his players believe they can win no matter who the opponent is and no matter who they have on the field.

"That's the thing about Chuck, he gives the team confidence," Hasselbeck said. "He has the ability to have the locker room believing that they are legitimate contenders. Chuck does a really good job -- whether it’s cliché or whatever, I think guys buy into it. I really do."