The Croatian defender has become a first-team regular at left-back for the Citizens since joining the club from RB Leipzig last summer, starting 28 times across all competitions.
Gvardiol, who has also played at centre-back, was named in the starting lineup for City's 4-2 win at Crystal Palace in the Premier League last weekend.
However, the 22-year-old was taken off at half time, with Guardiola stating after the match that the defender «felt a niggle and we didn't want to risk any injuries.»
Gvardiol was not spotted in an open training session on Monday afternoon, but he has been selected in Man City's 21-man travelling squad, unlike both Kyle Walker and Nathan Ake who have not made the trip to Spain.
Guardiola issues Gvardiol, Walker, Ake injury updateAhead of Tuesday's Champions League showdown, Guardiola has confirmed that both Walker (hamstring) and Ake (unspecified) are still injured, while a late call will be made on Gvardiol's availability.
"[Gvardiol] travelled but he is a doubt," Guardiola said at a press conference on Monday evening.
«It is what it is. Also Madrid have [Thibaut] Courtois, [Eder] Militao and [David] Alaba, a long time they have been without players.
»It's true that the best player to control a player like Vinicius Junior is Kyle. He unfortunately, in a friendly game (on international duty with England), was injured. We would love to have him but what can I say?
«Injuries are part of a long season, but unfortunately in a decisive part of the season we have a number of injuries in the same area and we have to find a solution.»
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