Aberdeen have confirmed that wantaway forward Duk will now face disciplinary proceedings after failing to turn up to training.
The club say they have made a number of attempts to communicate with the 24-year-old without reply.
A club spokesperson said: “Duk has failed to report to training and is currently absent without permission.
“The club has made attempts to communicate with Duk but he has refused to engage with us directly.
“He is now subject to internal disciplinary proceedings.
“We’re naturally disappointed with the situation but can’t say anything further at this stage.”
At a press conference on Friday, Aberdeen head coach Jimmy Thelin revealed Duk would not be in the squad to face Queen of the South on Saturday in the League Cup due to “internal issues”.
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New Aberdeen boss Jimmy Thelin discusses his plans for the season ahead as he prepares to face St Johnstone in their opening Premiership game, live on Sky Sports
He said: “Duk is not going to be in the squad. Right now we have some internal issues about Duk’s situation. That is all that I can say about that.”
It is understood Duk is looking to move this summer as he enters the final year of his contract at Pittodrie.
Sky Sports News revealed in January that Aberdeen rejected a bid from Spanish club Leganes for the forward.
Miovski on Bologna’s radar
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Aberdeen chief executive Alan Burrows is expecting bids for Bojan Miovski and Duk but insists they will not be sold on the cheap
Bologna are interested in Aberdeen striker Bojan Miovski.
It is understood the North Macedonia international is high up on the Serie A club’s target list as they look to replace Joshua Zirkzee, who is set to join Manchester United.
A number of clubs across Europe and in England have been monitoring Miovski for some time, with the Dons receiving a number of enquiries for him in January.
The 25-year-old scored 26 goals for Aberdeen last season.
When does the summer transfer window open and close?
The 2024 summer transfer window in the Premier League and Scottish Premiership is officially open.
The window will close on August 30 at 11pm UK time in England and at 11.30pm in Scotland.
The Premier League and Scottish Premiership brought forward Deadline Day to link up with the other major leagues in Europe. The closing dates were set following discussions with the leagues in England, Germany, Italy, Spain and France.