Los Merengues take on Pep Guardiola's side at the Etihad Stadium, as they attempt to overturn a 2-1 deficit from the first meeting at Santiago Bernabeu back in February.
Bale will play no part in their hopes of a comeback however, after the Welshman was not included in Madrid's squad list for the upcoming tie in Manchester, throwing his future with Los Blancos into further doubt.
The writing has been on the wall for the 31-year-old for some time, after coach Zinedine Zidane actively attempted to sell the forward last summer. The club decided to hold on to the four-time Champions League winner, although he has barely featured since.
Bale made 16 league appearances over the course of their title-winning campaign, but he struggled for minutes in the second half of the season, starting only once since La Liga's restart in June.
The ex-Tottenham Hotspur man still managed to draw plenty of attention in those weeks however, catching the eye with his playful - if somewhat churlish - antics from the substitute's bench. Bale was pictured using his protective equipment as a sleep mask, while pretending to use a pair of binoculars on another occasion.
Whether his behaviour had any influence over ZIdane's decision is unlikely, but his popularity within the Madrid fanbase has continued to plummet.
Another man who will not feature against the Citizens is James Rodriguez. The Colombian star has suffered at the hands of his French coach, who wanted to offload the midfielder to rivals Atletico Madrid last summer.
Rodriguez has taken to the pitch on even fewer occasions than Bale, making only eight appearances in La Liga this year, and his time at the club also appears to be reaching its end.