Aberdeen hope to finalise a deal to sign Paul Hartley on Wednesday.
The 33-year-old midfielder watched the Dons in action on Tuesday night as they won 1-0 at Port Vale.
Hartley has been allowed to leave Bristol City halfway through his contract after expressing a desire to return to Scotland and Aberdeen stepped up their interest after a return to Hearts fell through.
Aberdeen manager Mark McGhee said: "A potential deal with Paul is at a well advanced stage. It is not concluded yet and things can always happen but we are working towards finalising a deal as quick as possible.
"We are very excited about that. He would be a big asset to us but we have to cross the line with it first."