McDonald was cut from the Socceroos squad on the eve of the last World Cup and has gone 24 games without scoring for his country, but gets another chance from coach Holger Osieck, while Kewell is absent while he tries to sort out his club future.
Captain Lucas Neill, who is also yet to secure a club for the upcoming season, is named to lead the squad, while Mark Schwarzer and Tim Cahill, who missed the two friendlies against Serbia and New Zealand, are back in the fold.
Korean-based defender Luke DeVere has been given his first call-up since early 2010 and could make his debut, while Japan-based Matthew Spiranovic is also called up as Osieck looks to the next generation.
Michael Zullo, James Troisi and Robbie Kruse have also been named, while Sasa Ognenovski has been left out.
Matt McKay is the only A-League based player with Jason Culina not considered as he regains full fitness.
Australia play Wales at Cardiff City Stadium on August 10.
Squad: Adam Federici (Reading), Mark Schwarzer (Fulham); Luke DeVere (Gyeongnam), Lucas Neill (unattached), Matthew Spiranovic (Urawa Red Diamonds), Rhys Williams (Middlesbrough), Michael Zullo (FC Utrecht); Tim Cahill (Everton), Brett Emerton (Blackburn), Luke Wilkshire (Dinamo Moscow), Neil Kilkenny (Bristol City), Matt McKay (Brisbane Roar), James Troisi (Kayserispor), Carl Valeri (Sassuolo); Scott McDonald (Middlesbrough), Brett Holman (AZ Alkmaar), Mile Jedinak (Crystal Palace), Robbie Kruse (Dusseldorf).