The 27-year-old has missed his side's last two matches after picking up a calf injury during the first leg of their Champions League quarter-final against Bayern Munich.
However, the Wales international took part in training earlier today and is now in line to feature against Barca for this weekend's crucial El Clasico showdown.
"Bale rejoined the group in a session in which the starting XI from Tuesday's game carried out drills using the ball, before training using the indoor facilities," read a club statement.
"Pepe continued his recovery process, while [Raphael] Varane trained alone out on the pitch."
Madrid currently enjoy a three-point lead over Barca at the top of La Liga.