The Colombian international was not at training at Carrington today and at van Gaal's pre-match press conference the United boss revealed that injury will keep him on the sidelines. Falcao also missed the match against Chelsea last weekend.
Fortunately for Van Gaal, Wayne Rooney returns from suspension to face City, and the United manager confirmed that the England international will slot straight back into the team.
Speaking to reporters he said: "He was never injured. He shall play, he is my captain."
Antonio Valencia was another injury doubt heading into the game, but the Ecuadorian international could feature although there are concerns about the availability of Marouane Fellaini and Adnan Januzaj.
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Social media speculation noted that neither could be seen in the Manchester United training pictures released from Carrington earlier on Friday.
Januzaj has started the recent games against West Brom and Chelsea but could be sacrificed for the returning Rooney anyway. Fellaini drew special praise from van Gaal during the press conference after his goal against West Brom after coming on as a substitute.
"He has to continue with that because then I am very pleased," Van Gaal said
The 1-1 draw against Chelsea last weekend was a positive result for United after previous poor results against the big teams last season. They travel to the Etihad, the scene of a humiliating 4-1 defeat last term, with their rivals currently stuck in a rut.
City have won just two of their last six games in all competitions, and have kept just two clean sheets in their opening nine Premier League matches.