Aberdeen attacker Duk is out of contract at the end of the season and free to sign a pre-contract with another club from the start of the winter transfer window on January 1.
Striker Miller's career was 'galvanised' by the right move after disappointing spells, and he thinks Thelin's Aberdeen are proving a good fit to help Millwall loanee Nisbet do the same.
Former Aberdeen skipper Lewis believes youth academy graduate left-back MacKenzie has earned a 'good contract' after an impressive campaign under Jimmy Thelin.