Bale missed the 3-2 win over Sporting Gijon and the 4-2 Champions League win over Bayern Munich with a calf injury but he gave Zinedine Zidane a boost when he was able to be named in the squad for the match.
Zidane has decided that he is fit enough to start and he will start in the front three alongside Cristiano Ronaldo and Karim Benzema.
Barcelona appealed Neymar's red card that the Brazilian was shown in the 2-0 defeat against Malaga but the ban has been upheld and he continues to serve a three-match ban.
In his absence Alcacer, the summer signing from Valencia, starts with Luis Suarez and Lionel Messi.
Jordi Alba starts at left-back as Luis Enrique goes with a back four rather than three.
Read the full article on eurosport.co.uk: El Clasico team news - Alcacer replaces Neymar, Bale starts