Bale played no part in the last six games of Madrid’s title-winning La Liga campaign and was omitted from Zinedine Zidane’s squad for their final game of the season against Leganes.
Zidane has left Bale out once again for the trip to the Etihad, with Madrid hoping to overturn a 2-1 deficit for February’s first leg at the Santiago Bernabeu.
The Wales international has not been named in a match day squad since his half-hearted celebrations of Madrid’s first domestic title in three years.
Bale stood back with his arms folded as his team-mates threw Zidane in the air following their decisive 2-1 win over Villarreal last month.
The 31-year-old was used sparingly once La Liga restarted in June, and was criticised in the Spanish press for pretending to sleep while watching a 2-0 win over Alaves from the substitutes’ bench.
Despite falling out of favour under Zidane, Bale has two years remaining on his contract at the Bernabeu and has shown little desire to leave in search of first-team football elsewhere.
James Rodriguez has also been left out of Madrid's squad and faces a similarly uncertain future in the Spanish capital after only playing once under Zidane post-lockdown.
Meanwhile Sergio Ramos, the Madrid captain, is listed as a member of Madrid’s travelling party for Friday night's return leg against at the Etihad despite being suspended.
Ramos was sent off during the closing stages of City's 2-1 first-leg victory but will join the rest of Zidane's squad in Manchester for motivational purposes.
Real Madrid’s squad to face Manchester City
Goalkeepers: Thibaut Courtois, Alphonse Areola, Diego Altube
Defenders: Dani Carvajal, Eder Militao, Sergio Ramos*, Raphael Varane, Nacho, Marcelo, Ferland Mendy, Javi Hernandez
Midfielders: Toni Kroos, Luka Modric, Casemiro, Fede Valverde, Isco
Forwards: Eden Hazard, Karim Benzema, Lucas Vazquez, Luka Jovic, Marco Asensio, Brahim Diaz, Vinicius Jr, Rodrygo