Despite being thought of as a top-three choice at this month's National Draft, Daniel Curtin has been overlooked as his class' best key defender by a renowned draft expert.

SEE ALSO: AFL DRAFT PROFILE -- DANIEL CURTIN

Curtin, Western Australia's unequivocal top prospect and a near-certainty to be swooped on within the count's first five selections, isn't preferred to his Allies counterpart, Connor O'Sullivan, in the eyes of renowned draft expert Mick Ablett.

O'Sullivan, a Murray Bushrangers graduate who also projects as a top-ten selection on November 20, is a versatile key defender in a similar mould to Curtin, who is extremely flexible positionally.

"I go straight to Connor O'Sullivan (when choosing the best key defender), he's a 198-centimetre centre-half-back," Ablett stated via SEN.

ADELAIDE, AUSTRALIA - JUNE 11: Connor O'Sullivan of the Allies during the 2023 U18 Championships match between Allies and Western Australia at Thebarton Oval on June 11, 2023 in Adelaide, Australia. (Photo by Sarah Reed/AFL Photos via Getty Images)

"He was in the Coates [Talent] League Team of the Year player in that particular position and he's the genuine swingman of this draft.

"We generally get one of them and I've likened him a little bit if [you] think of an Oscar Allen-type player.

SEE ALSO: AFL DRAFT PROFILE -- CONNOR O'SULLIVAN

"If you go back to some earlier days, it's like how Darcy Moore had [that] ability to play centre-half-forward and [as] a half-back."

Ablett didn't stop at O'Sullivan's defending talents, lauding his ability to utilise his foot skills to kickstart offensive movements.

"This guy is just a beautiful attacking option in either one of those positions, particularly down back where he really likes to slingshot," Ablett said.

"He takes the ball deep, he takes off and attacks at every opportunity. But having said that, he's also got a really nice level of composure.

"He does want to go and take the game on, but he's also got the ability to sum the situation up, compose himself, change direction and hit a target somewhere where he wasn't necessarily moving in the first place.

"There's a lot to like about Connor O'Sullivan."

O'Sullivan went to Melbourne with Pick 4 in Zero Hanger Chief Editor and draft expert Mitchell Keating's second edition Mock Draft, while Curtin was snatched up No. 4 overall by North Melbourne.