Bale has not appeared for Spurs this season, and was pictured in Spain over the weekend. He missed Wales's recent friendly against Ireland due to a foot problem that has troubled him since July.
Aaron Ramsey has also been named in the squad, despite leaving the pitch with a groin injury after scoring both of Arsenal's goals in a 2-0 Champions League play-off victory over Fenerbahce on Wednesday.
Wales, who are 13 points behind Group A leaders Belgium and 10 off second-placed Croatia, play Macedonia in Skopje on September 6, followed by Serbia in Cardiff on September 10.
Spurs boss Andre Villas-Boas said his move to Real Madrid is on the verge of completion.
"It could happen very, very soon," the Portuguese said. "It's a dream move for him.
"Tottenham will accept most likely the biggest transfer in world football."