CALLUM Mills has been a member of the Sydney Swans academy since he was 13, he trained with the club's senior team for five weeks before Christmas and, as one of the top players in the 2015 draft crop, appears headed there at the end of this year as a zone selection.

He barracks for the Swans, is close family friends with club chairman Andrew Pridham and idolised champion goalkicker Tony Lockett when he was growing up.

Since dropping a promising rugby union junior career in his teens, Mills' focus has been on one day playing for the red and white. 

But last week saw Mills swap colours (albeit momentarily) to train and be embedded at another club – the Swans' crosstown rivals Greater Western Sydney.

The NAB AFL Academy sends each of its 35 squad members for two separate placements at different clubs, and given Mills' extended time with the Swans in December, the New South Wales prospect was allotted to the Giants for his January experience.

Having been linked to the Swans for some time and developed his game there, the midfielder expected it to feel strange stepping into a new place and environment, but found it otherwise.

"It was a real eye-opener seeing something different to what I'm used to. But I loved it, everyone was good to me," Mills told AFL.com.au in Tampa in the US on the AFL Academy's 10-day training camp.

"I thought it was going to be strange, to be honest, but when I got there everyone was really welcoming to me and no one really thought of it. I thought it might be weird between coaches and thought it might be awkward, but it didn't end up like that at all and I really enjoyed the week."

It seems unlikely Mills will again don the Giants' orange and charcoal. The 17-year-old has been pegged as a standout of this year's draft pool, with many viewing him as an early candidate as the best player in the crop.

His qualities have already been on show in the early part of the American camp: he's a competitive, hard-nosed ball-winner who loves the contest and, at 188cm and 80kg, would fit well into any midfield.

But with Mills a member of the Swans academy, they will get first-access to him, even if structures around the father-son and academy bidding system are changed by the end of the season.

As debate raged over the fairness of the academies last year, attention focused on Isaac Heeney, who was widely considered a top-five talent but was secured by the Swans with pick 18 under the bidding rules.

Mills saw how Heeney handled that focus and stayed humble throughout it, and thinks he'll pick his brain about it again.

"I've had a talk to him about it before and I guess I'll have another chat with him this year when footy starts to kick in more, but the way he dealt with it was to ignore it was there," he said.

The AFL Academy group arrived in Tampa on Saturday, and started training at the IMG Academy facilities on Sunday, where the group will stay this week before visiting Orlando.

The squad was put through a gruelling fitness session on Monday morning that included a three-kilometre time trial, fartlek speed running and a conditioning program before finishing with hill runs back and forth and the man-made mounds.

All the work feeds into Mills' aims for the trip.

"I really want to challenge myself, get through obstacles and do things I've never done before," he said.

"It's good to test your body and see how you go."