Andrew Hoole is set to be key to whether David Carney joins Sydney FC after the Newcastle Jets agreed to release their star playmaker to the Sky Blues only in exchange for the young forward.

The saga involving Carney's proposed return to Sydney will go down to the final day of the transfer window as talks continued between the two clubs and representatives of both players on Monday night, with a decision set to be made by Tuesday - the final day of the A-League transfer window.

Player exchange: David Carney's deal with Sydney FC rests on Andrew Hoole agreeing to leave Sydney for the Newcastle Jets. Credit:Getty Images

Under the proposal, 22-year-old forward Hoole will be on his way back to Newcastle after just 11 games for the Sky Blues should he accept an increased offer from his hometown club and trade places with former Socceroo and close friend, Carney. The Jets are understood to have requested the services of Hoole in exchange for releasing Carney to their rivals despite the veteran being regarded as their best performer this season.

Speculation the 32-year-old had played his last game for the Jets surfaced after he was omitted from their squad that played Adelaide on Sunday.