ADELAIDE, AUSTRALIA - AUGUST 13: Ben McKay of the Kangaroos leads thje team off at half time during the round 22 AFL match between the Adelaide Crows and the North Melbourne Kangaroos at Adelaide Oval on August 13, 2022 in Adelaide, Australia. (Photo by Mark Brake/Getty Images)

Clubs interested in North Melbourne free agent Ben McKay have reportedly come away from the key defender's medical testing with some concern regarding a knee issue for the unsigned Kangaroo.

McKay's future remains up in the air as he assesses the open market with the ability to exercise his rights as a free agent, with as many as four clubs having shown strong interest in the 25-year-old this year.

Hawthorn and Essendon loom as the leading parties in the pursuit of the 202cm defender, with both Port Adelaide and Sydney said to be out of the race.

With the chase for McKay's signature narrowed to two clubs and closing in on a final decision, clubs who have had the Kangaroos backman undergo medical testing as part of their recruitment process are understood to have come away from the examinations with some concern, according to 7 News' Mitch Cleary.

A knee issue has seen "some question marks raised" around McKay, who also missed the start of this season with a foot issue, however those concerns aren't likely to impact a deal for McKay.

"It's my understanding there has been some question marks raised around the medical and a potential knee (concern) and what that looks like in the long term," Cleary told Talking Finals on Wednesday.

MELBOURNE, AUSTRALIA - MAY 20: Ben McKay of the Kangaroos handballs during the round 10 AFL match between North Melbourne Kangaroos and Sydney Swans at Marvel Stadium, on May 20, 2023, in Melbourne, Australia. (Photo by Daniel Pockett/Getty Images)

"Not enough, I don't think, to change or alter the deals put in front of Ben McKay, but it is just a query as this continues to drag on and we await an answer from Ben McKay on what it looks like for the future of him at those two clubs."

North Melbourne are expected to secure band one compensation if McKay departs, with a lucrative deal likely to be signed if he chooses either the Hawks or Bombers.

Should an agreed offer fall below the likely top-level for compensation, the Kangaroos are prepared to match the offer given McKay is a restricted free agent, meaning a trade between North Melbourne and the bidder would need to take place for a move to be granted.

GWS forced Geelong to trade for free agency Jeremy Cameron in 2020 after the Cats' bid was matched by the New South Wales club, with Geelong eventually parting with a trio of top 20 draft selections for Cameron and a pair of second-round picks.

"Like the Cats did with Jeremy Cameron and the Giants, (the Kangaroos) can force the club into a trade and then maybe he stays at North Melbourne," Cleary said.

"At this stage, if the deal is big enough he will leave North Melbourne, who could get Pick 3 (as compensation)."

The 2023 free agency window is set to open on Friday, October 6 and will run until 5:00pm (AEST) on October 13.