INDIANAPOLIS – They’ve done virtually everything possible. They’ve crossed the t’s and dotted the i’s, and tailored the playbook accordingly.

Shane Steichen and the Indianapolis Colts’ offensive staff have molded and nurtured their young quarterback – Anthony Richardson, you’ve probably heard of him – since Chris Ballard selected him with the No. 4 overall pick in the April draft.

There was a rookie minicamp, the offseason workout program, OTAs, veteran minicamp, training camp, joint practices with the Chicago Bears and Philadelphia Eagles and preseason appearances against the Buffalo Bills and Eagles.

There have been meetings, and more meetings.

Richardson spent roughly eight hours on Tuesday – that’s the players’ normal day off – at the Indiana Farm Bureau Football Center because that’s how quarterbacks prepare for the upcoming game.

That’s especially how a young one should prepare.

“That’s part of the job,’’ Richardson said. “Putting in extra work, getting ready for the game because I know other people are putting in extra work. My teammates are putting in extra work because I see them in the building as well.’’

When Richardson jogs out of the Lucas Oil Stadium tunnel Sunday against the Jacksonville Jaguars, he’ll be the youngest starting quarterback in Colts’ history at 21 years and 111 days, and the third-youngest in the NFL since 1970. Only Denver’s Tommy Maddox (21 years, 81 days in 1992) and the New York Jets’ Sam Darnold (21, 97 in 2018) were younger.

What tells Richardson he’s as ready as possible for what’s to come?

“The trust from my teammates and the coaches,’’ he said Wednesday afternoon. “Them believing in me and trusting me and me knowing my information. That lets me know I’m ready.’’

Despite the depth of preparation, an unsettling reality invariably lurks on Sunday.

“It’s just the unknown. You know what I mean?’’ Steichen said. “You’re going to get some looks that you probably haven’t seen on tape. You’re going against new bodies, new personnel. I think that’s the biggest thing: Just understanding what you’re going up against and being ready for the unknown because it’s not going to be perfect out there and as coaches, we’ve got to be able to adjust on the sidelines to help these guys make plays.’’

Jacksonville coach Doug Pederson has done his due diligence as well. He’s studied the young QB who’ll test his defense.

He’s impressed.

“I mean, it’s tough,’’ Pederson said. “You think of him, you think of Cam Newton.’’

Newton, lest you’ve forgotten, was the Carolina Panthers’ big (6’5″, 245-pound), strong, dual-threat quarterback who was the NFL’s MVP in 2015.

“These are big, physical, strong quarterbacks that can also throw the football,’’ Pederson said. “And they’re athletic. It is a challenge. When you watch the tape, (Richardson) can break arm tackles. And then he can run for 15, 20, 30, 40 yards and beat you with his legs.’’

Richardson’s athleticism and versatility were on display in his two preseason appearances – 45 yards on seven rushes – but Steichen and coordinator Jim Bob Cooter showed very little of what a Richardson-led offense will actually look like starting Sunday. Determining how best to tap into his unique skills included doing a deep dive into what worked for Richardson in his 13 starts at Florida.

“You try to take advantage of the things he’s really good at and let him go execute on Sundays,’’ Steichen said.

Everyone should expect Richardson and running backs Zack Moss and Deon Jackson to stress the edges of Jacksonville’s defense with their RPO game. And there will be occasions when Richardson must push the football down the field in the passing game.

One of the glaring deficiencies in the Colts’ offense last season was the lack of anything resembling a deep passing threat. Quarterbacks averaged 6.4 yards per attempt (No. 29 in the league) and receivers averaged 9.7 yards per reception, the lowest in franchise history.

“Obviously, you want to be explosive in the pass game,’’ said Steichen, who considers yards-per-attempt one of the most telling barometers for a successful pass game. “Just being efficient. Completion percentage is a big part of it, but at the same time you want to create the explosive plays.’’

It’s a lot to pile on the plate of a rookie with such a thin college resume. Run when the defense gives you the appropriate look. Make plays with your arm when they’re there. Take care of the football, but be aggressive.

To this point, Richardson has given every indication he’s up to the challenge.

And let’s not dismiss the enormity of that challenge. He’ll be just the seventh rookie quarterback to start a season opener in franchise history. The only one to win his NFL debut: George Shaw. In 1955.

Keeping in mind rookie quarterbacks usually are thrust into less-than-desirable situations, no one should be surprised by the lack of collective success: 49.67% accuracy, five touchdowns, eight interceptions, 16 sacks and a 59.5 passer rating.

The Colts aren’t guaranteeing Richardson will lead them to their first season-opening win since 2013, but are sure they’re following the right guy.

“I’m confident,’’ said defensive tackle DeForest Buckner. “I’m confident in his abilities and what he’s been able to put on tape so far. I’m confident the vets, especially on the offensive side, will rally around him. The defense is going to rally around him no matter what happens. The team’s going to have his back.’’

“I’m confident. I’ve got all the faith in the world in him, ” added All-Pro guard Quenton Nelson. “And he’s not out there alone. He’s got 10 other guys with him. We need to do our jobs to the best of our ability to make his job easier. Then on the field, just how special he is. He can run the ball, he can throw, he can do it all. He’s special.’’

You can follow Mike Chappell on Twitter at @mchappell51.