The in-form 23-year-old winger picked up a "knock" in training ahead of the Nedbank Cup penalty shootout win over Cape Town City.
Thikazi has netted five goals for his DStv Premiership club this season, alongside one assist.
Head coach John Maduka confirmed the news, on iDiski Times: "Mfundo Thikazi is out for two weeks have a knock two days before this game that we just played.
"So we have no choice, it's one of the things. He got a knock, he will probably take two to three weeks then he will be back."
Royal AM face AmaZulu in their next league encounter at the weekend.