Reigning Olympic champion Xander Schauffele, the world number five seeking his first major title, will complete the feature trio from the field of 89, which includes 20 Masters newcomers.
Scheffler, fancied by oddsmakers, could join 15-time major winner Tiger Woods as the only players to win the Masters twice while ranked world number one.
The American has seven top-10 finishes in eight starts this year, including wins at The Players Championship and Arnold Palmer Championship.
But Scheffler's trademark discipline and composure won't let him ponder the impact of a second green jacket in three seasons.
"I try not to look too far into the future," he said. "I'm excited about how I've been playing to begin this year.
"All I'm trying to do is put myself in contention in the tournament and hopefully finish it off. I really am not looking much past tomorrow. I'm focused on my preparation."
McIlroy, a four-time major winner from Northern Ireland, knows all too well that a Masters triumph would complete a career grand slam. It's the 10th time he has tried to finish the feat since winning his most recent majors in 2014.
"I've already got most of my prep work done, so it's just about going out there and being relaxed and being in the right frame of mind," McIlroy said. "The more I can do that, the more I'll be able to execute on the golf course."
McIlroy, a 2022 Masters runner-up to Scheffler, has six top-10 finishes in his past nine starts at Augusta.
Among those confident McIlroy will complete the career grand slam is five-time Masters champion Woods.
"No question, he'll do it at some point," Woods said. "Rory is too talented, too good. He's going to be playing this event for a very long time. He'll get it done. It's just a matter of when.
"I think Rory will be a great Masters champion one day and it could be this week. You never know. I just think that the talent he has, the way he plays the game and the golf course fits his eye, it's just a matter of time."
It was a motivational boost for McIlroy, whose decade-long major win drought includes 10 top-five finishes and three runner-up efforts, including last year's US Open.
"It's flattering. It's nice to hear, in my opinion, the best player ever to play the game say something like that," McIlroy said.
"Does that mean it's going to happen? Obviously not. But he has been around the game long enough to know I at least have the potential to do it. I know I've got the potential to do it too. It's not as if I haven't been a pretty good player for the last couple decades.
"But yeah, it's nice to hear it when it comes out of his mouth."
'I can get one more'
Woods, a five-time Masters winner, is trying to make a record 24th consecutive Masters cut, surpassing the current mark he shares with Gary Player and Fred Couples.
The 48-year-old American says he still has what it takes to match the record six green jackets won by Jack Nicklaus despite severe leg injuries from a 2021 car crash and ankle surgery last April.
"If everything comes together, I think I can get one more," Woods said.
Woods admits he aches every day, an ill omen as he struggles to walk 72 holes at Augusta National.
"It's certainly one of the more hillier walks that we have on tour," Woods said.
Third-ranked Jon Rahm will try to join Woods, Nicklaus and Nick Faldo as the only players to win back-to-back Masters titles.
He's among 13 players from the Saudi-backed LIV Golf League in the Masters field, having made the jump from the PGA Tour last December.
Among those playing their first Masters are fourth-ranked Wyndham Clark, the reigning US Open champion, and world number nine Ludvig Aberg of Sweden. No rookie has won the green jacket since Fuzzy Zoeller in 1979.
