INDIANAPOLIS — With all the trails and tribulations that Andrew Luck has experienced since undergoing shoulder surgery in January 2017, he wondered at times when he'd get the chance to play in a meaningful football game ever again.

Yet here we are, four days away from the Indianapolis Colts' 2018 season opener against the Cincinnati Bengals, and any questions about Luck's health, and his availability, were already answered weeks ago.

Luck on Sunday will play in his first regular season NFL game in 616 days, and, as it pertains to his recovery and rehab work, the boxes have virtually all been checked by now. 

Now all Luck has to worry about is how to beat the defense across from him — easy, right?

"I feel really good, and I'm really excited," Luck told reporters on Wednesday. "I feel like I'm in shape, I feel I can make all the throws that I need to. I'd like to think that I can keep improving as a quarterback, that I can keep improving as a football player, keep improving as an athlete — you know, I like to think this team will improve as we go through this season. But very excited."

The so-called "boxes" have really been the pillars of Luck's rehab work since he was officially shut down last November and placed on injured reserve. With a renewed focus, Luck has moved from working with weighted balls, miniature footballs, high school-sized footballs and, finally, by the end of the offseason workout program, regulation NFL footballs.

At each stop, Luck noted, he wasn't feeling the pain that he experienced last year in his initial attempt to get back onto the field for the 2017 season. So he continued to move on; continued to check off boxes.

Luck ramped up his throwing program working out on his own, and, by the start of training camp, was able to handle a full practice load. He played in his first preseason game Aug. 9, and then played a few more snaps 11 days later. By Aug. 25, he wrapped up his preseason by tossing a 15-yard touchdown pass to tight end Eric Ebron, heading into the regular season with the confidence that he'd be ready to go by Week 1.

Now, for Luck, the time for checking boxes is over, as it pertains to his "comeback." It's just time to play some football.

"What's exciting for our team and our fans is that we get him for 60 minutes," Colts head coach Frank Reich said of Luck on Wednesday. "The longer a guy like that is out on the field, the better."

"I know personally I feel like I've gotten better and improved a bunch — sort of been on the right arc, been on the right path, per se," Luck said. "I think this team's been on the right arc and the right path. And I think we're enjoying the journey. I think Frank does a great job of keeping us locked in on the process. And we'll stay that way; this journey doesn't end because real games are starting. One, we go out to try to win; two, we've got to make sure we're getting better and improving."