Scott McKenna is the subject of a significant offer from English Championship club Nottingham Forrest.
The big defender has been left out of Aberdeen 's side for today's Premiership match with Motherwell and the club moved to confirm a deal is in the offing.
The Dons said on Twitter: "Aberdeen manager Derek McInnes confirmed on RedTV that the club has received a significant offer for Scott McKenna.
"This is now being dealt with by the Chairman and the relevant club."
Sabri Lamouchi's side have started the season poorly with a pair of 2-0 defeats from QPR and Cardiff and have been looking for new recruits to boost their chances on improving on last season's seventh place finish.
McKenna has been the subject of transfer interest before with Aston Villa bidding £7m for the strapping stopper in 2018 but the deal fell through as the Dons held out for more money.
In the time since, the 23-year-old has become a first pick for Scotland and has amassed 16 caps.