Midfielder McGrath has agreed a pre-contract to join Hibs in the summer as Aberdeen battle with the Easter Road club - who visit Pittodrie on Saturday - to finish third.
Aberdeen manager also confirms an injury setback for striker Ester Sokler and delivers updates on Kristers Tobers and Sivert Heltne Nilsen.
Aberdeen boss Thelin inherited a team that finished in the Premiership bottom six and has led them to the Scottish Cup final and a fight to finish third.
Aberdeen have received a bumper six-figure cash boost due to an initiative agreed by the UEFA Executive Committee.
The Press and Journal can confirm Aberdeen are set to sign the Western Sydney Wanderers winger, with a £400,000 (800,000 Australian dollars) price-tag reported Down Under.
The Reds have lost only one of the 11 games Knoester has featured in since joining from Ferencvaros.
