The Welsh winger missed Saturday's 3-0 win over Eibar due to a foot injury but was back training with Real coach Carlo Ancelotti on Sunday.
The reigning European champions face their local rivals across town at Atletico's Vicente Calderon on Tuesday, and Bale could be ready to play.
Bale had scored five goals in as many games in all competitions before injury struck.
The starting XI that led Real to victory in La Liga against Eibar were given a light session on Sunday.