ABOUT four weeks ago, Luke McDonald approached Vic Metro coach Rohan Welsh and state talent manager Anton Grbac with a question. The gifted 17-year-old, who has moved to defence this year after playing mostly as a forward and midfielder through his career, wanted to set himself a challenge.

If he got picked - and McDonald did say "if" - for Metro's clash with South Australia in the third round of the NAB AFL Under-18 Championships, he wanted to play on Sam Mayes, who is viewed as one of the country's premier forwards of this year's NAB AFL Draft and a member of the AIS-AFL Academy. 

Click here for the full coverage of the NAB AFL U18 Championships

"It was a personal challenge for him," says Grbac. "Why not give him a go?"

McDonald did play on Mayes, and played very well. He kept up with him on the lead, beat him when the ball was on the ground, and set up the play for his team off half-back with his spearing left-foot and smart decision-making.

Mayes finished with just 10 touches (some of them were when he moved into the midfield), while McDonald collected 13 disposals in Metro's win, ignoring some of his attacking instincts to complete the shutdown job for his team.

"You're not going to get better unless you play on better opponents and Sam is one of the best forwards there is this year, so when the opportunity arose to play on him I was jumping all over it," McDonald told AFL.com.au.

"I'd heard a lot about him, but I'd actually never seen him play before. I've never seen someone run so much in my life. I learned a bit off playing on such a talented player but it was good to get a big scalp like that."

It only cemented thoughts already widely held about McDonald: that he's a modern AFL prospect, able to play nearly anywhere, perfectly sized at 187cm, with a real competitive streak and all the other traits every club would like in one of its draftees.

But here's the other thing about McDonald - soon he'll be off the market, with him on the verge of committing to North Melbourne under the father-son rule.

McDonald's dad, Donald, played 155 games at the club between 1982-92 and is now the club's football manager. Even though Luke is a bottom-age player (meaning he can not officially join an AFL club until the 2013 draft), the two parties can agree to a long-term deal that ties him to the club and lets the Kangaroos fast-track his development next year.

But he does have options. He is eligible for this year's Greater Western Sydney mini-draft, and if he nominated (which he has to do by July 31) he is considered a strong chance to be one of two 17-year-olds taken by clubs. He could also choose to go his own way and nominate for next year's NAB AFL Draft, where he is available to any club at any pick. 

McDonald, though, is only interested in one thing, and that's playing for North. He wants to turn his dream into his day job. 

"We're still working it out with my manager Paul Connors. It's a pretty lengthy process," McDonald said.

"I want to play for North Melbourne, so hopefully Paul can work out a deal with them which satisfies both North and I. I definitely want to play there. Obviously the mini-draft is there and I've spoken to a few people about it, but at the end of the day I've gone for North since I was a little kid.

"I'm a pretty passionate North Melbourne supporter so I want to do whatever I can to help bring them up. They've got a pretty young list so it's a pretty exciting time there and I'd love to be a part of it."

McDonald has already been anointed as a player of the future. He is a member of the AIS-AFL Academy's level one group, and at the start of this year was an impressive contributor for the Oakleigh Chargers in the TAC Cup.

He started playing for Trinity Grammar's first XVIII side as a year 10. Rohan Brown, the school's teacher in charge of football, jokes that McDonald, now one of Trinity's co-captains, might need to return through the seconds if he is to get back into the school's undefeated side after the national carnival. 

Aside from McDonald's will to win any contest ("A lot of people hate losing but it does burn inside me when I do," he says), his speed and kicking sets him apart. Although his father was more of a key position player, Luke can also kick long and precisely like Donald, and it's an area that is still being refined. 

"In the past 12 months he's had to work on being able to lower his eyes and hit up shorter targets," says Mark Smart, Chargers region manager. "Because his kicking is so good he just needed to realise at times that he doesn't need to blaze away, and he's worked really hard at that."

He's also learning about keeping things in check, with his laid back demeanour making it easy to deal with more attention his football is getting. But that doesn't mean he's not thinking about the possibilities.

McDonald finishes his year 12 at the end of this year, and wants to keep going with a university course in 2013. That, too, has a blue and white striped slant.

"It'd be nice, if I was at North, I could go to Melbourne Uni because it's so close but that's a big ask," he said with a smile.

"I was looking at commerce at Melbourne but I think that's a pretty high ATAR score. You have to get 93 [which would put McDonald in the top seven per cent of the state], so that's what I'm aiming for. It'd be perfect, but obviously a few things have to happen before then."

Callum Twomey is a reporter for the AFL website. Follow him on Twitter at AFL_CalTwomey.