Aaron Francis deserved all of his plaudits as a standout in South Australia's NAB AFL Under-18 Championships this year, but there was another defender alongside the top-10 prospect who kickstarted his rise up the draft board.

Riley Bonner was a key member of the state side and a vital part of its game plan during the carnival, with the powerful, long-kicking half-back given responsibility to set up his team's attacking forays.

He played the role well and won All Australian selection for his carnival, when he played all six games for his state.

Bonner has tasted the senior level of the SANFL this year with West Adelaide, but has spent the majority of the season in the club's reserves and under-18s sides. At under-18 level he averaged 23 disposals and six inside-50 entries a game, showing his class a little further up the ground.

Bonner generates lots of run. He bursts down the field from defence and sets up the play, but is more than happy to quickly track back and find his man. He is good at spotting a chance and going for it: he can see space, accelerate away and get his team moving.

By far Bonner's best trait is his long and penetrating left-foot disposal. In an instant he can have the ball in his team's forward half. He averaged 18 disposals at the championships at a disposal efficiency of 73 per cent, and makes the right decisions with the ball in his hands.

Bonner's size also gives him an advantage. At 191cm he can play against taller forwards or take on the smaller types, and in time he might also be stationed further up the ground on a wing. Bonner is deceptively tall and stronger than most half-backs also in first-round contention.

He can become more consistent with his one-on-one work in defence, as he occasionally finds himself out of position in marking contests. But that seems like something that will improve as Bonner spends more time in the backline, as he is relatively new to the role.

He didn't test at the NAB AFL Draft Combine as he nursed a foot injury in a moon boot, but that won't be a concern.

It's not hard to se why Bonner has drawn comparisons to Hawthorn premiership defender Grant Birchall. He's similarly sized and plays in the same spot off half-back, where he gives his drive. Like Birchall, Bonner can match-up on a range of different forwards.

Bonner is a possible top-20 pick at the draft. Because of his versatility and foot skills, he appeals as a damaging player. His name should fit somewhere in the 15-25 range of the draft.

It's easy to see why clubs like Bonner. He has the skill set to be able to cut through the game and make it look easy. Recruiters look at prospects wondering how they can fit into an AFL team. They wouldn't need to search for a spot for Bonner, because his left-foot is a serious weapon.