Rory McIlroy said golf's biggest stars must rally around Tiger Woods by making regular trips to his Florida mansion and he would love to be part of the sport's Grand Slam club by his next visit.

After winning an Open Championship, a U.S. Open and two US PGA Championships early in his career, McIlroy returns to Augusta for another shot at Masters glory this week.

Woods, who suffered serious leg injuries in a February car crash, would love to be involved but is recovering at home after that brush with disaster and hopes to play competitive golf again.

The American superstar became the first player since the 1960s to win all four of the sport's majors in his career when he landed the Open title in 2000 at St Andrews.

With 15 career majors, Woods is unmistakably an all-time great, and McIlroy would become just the sixth player to achieve the modern Grand Slam should he land green jacket glory. Jack Nicklaus, Gene Sarazen, Ben Hogan and Gary Player are the players who achieved the feat before Woods came on the scene.

Speaking about the absent Woods ahead of Thursday's opening round, former world number one McIlroy said: "Hopefully, if his recovery goes well, who knows, he could be back in 12 months' time.

"He's always missed when he doesn't play in these big events, and that doesn't change this week, whether it's to do with his back or his leg or whatever it is.

"I know he's at home and he's fully focused on the recovery process, and I feel like he's mentally strong enough to get through that. And once he does, broken bones heel, and he's just got to take it step by step.

"I'm sure he's going to put everything he has into trying to be ready to play here next year. I went over and saw him, spent a couple hours with him, which was nice. It was good to see him. It was good to see him in decent spirits.

"When you hear of these things and you look at the car and you see the crash, you think he's going to be in a hospital bed for six months. But he was actually doing better than that. A few of us that live down in South Florida went to see him. I'm sure he appreciates that.

"I think myself, JT [Justin Thomas], Rickie [Fowler], DJ [Dustin Johnson], Brooks [Koepka], all those guys down there, we all have a responsibility to try to keep his spirits up and keep him going and try to get him back out here."

Nothing would give McIlroy more pleasure than being able to visit Woods as a Masters champion, with that Grand Slam monkey off his back. He has six top-10 finishes at the event in the last seven years, which shows what he has to offer.

The Masters is the mountain he has been unable to quite climb, meaning the 'Rory Slam' has yet to be completed.

"If I were able to do it, I'd join a very small list of golfers in history that have been able to do it. So I know where it would put me in the game and how cool it would be, and I would love to do it one day," McIlroy said.

"But for me to do that, I just have to go out and try to play four good rounds of golf on this golf course. I've played a bunch of really good rounds on this golf course before, but just not four in a row."

McIlroy revealed his visit to Woods' home in late March was an eye-opener, in terms of learning how his friend and rival has approached competing over the years.

"In his family room he's got his trophy cabinet and it's his 15 major trophies. I said, 'That's really cool. Where are all the others?'," McIlroy said.

"He said, 'I don't know'. I go, 'What?'. He said, 'Yeah, my mom has some, and a few are in the office and a few are wherever'."

It struck McIlroy, as he was driving home from that visit, that the majors were the be-all and end-all for Woods.

"I'm just thinking to myself, how easy must that have felt for him if all he cared about were four weeks a year. The other stuff must have been like practice. So that's like a really cool perspective to have, right," McIlroy said.

"That's all I could think about on the way home. And I was glad he was OK, too."

McIlroy has been working with coach Pete Cowen on simplifying his technique, saying he is "just at the start of a journey here that I know will get me back to where I want to be".

Three-time Masters champion Phil Mickelson is also taking part this week, the 50-year-old being a U.S. Open short of a Grand Slam himself.

His prospects of completing the full set look to be slim given he is not the force he once was, but Mickelson has the capacity to surprise and would love another Augusta challenge.

Many consider McIlroy's game to be well suited to The Masters, and Mickelson always knew his own skillset was perfect for the course.

"I never really doubted that I would end up winning this tournament," Mickelson said on Tuesday. "This is a course that is very well suited for the way I grew up playing, but that joy of winning it for the first time, finally breaking through, it's beyond belief."