The Wales international suffered a calf injury in the 2-1 UEFA Champions League quarter-final, first-leg win over Bayern Munich at the Allianz Arena on April 12.
He missed the 3-2 LaLiga win over Sporting Gijon last weekend and the return fixture against Bayern in midweek, in which Madrid triumphed 4-2 to progress to the semi-finals.
Bale completed a session with the starting XI from that game early on Thursday, which included drills with the ball and the use of the indoor facilities, Madrid confirmed.
It remains unclear whether the 27-year-old will be risked for Barca's visit to Santiago Bernabeu.
A win will see Madrid move six points clear at the top of the table, with a game in hand over the champions.
While Zinedine Zidane ponders whether to reunited his 'BBC' front line of Bale, Karim Benzema and Cristiano Ronaldo, Luis Enrique will not be able to call on a full complement of 'MSN' attackers, as Neymar is suspended.