Mitchell clashed heads with winger Clyde Rathbone in a practice session in Coffs Harbour and while precautionary X-rays confirmed a break, the Wallabies do not believe he will require surgery.
"The X-ray showed that Drew has suffered a fracture to his jaw," Wallabies team doctor Martin Raftery said.
"His jaw wasn't displaced in the collision and his bite is okay, so at this point it doesn't appear that he will need surgery."
Mitchell will not be able to take part in physical contact sessions over the next fortnight and medical staff will review his fitness when the team gather in Sydney prior to leaving for their European tour.
However, officials have confirmed Mitchell will remain with the squad in Coffs Harbour until Friday when team members return home to continue their strength training.