The Belgium midfielder suffered the latest of several injuries this season when he was forced off in the champions' Premier League win at home to Tottenham on Saturday.
"It is a muscular problem," Guardiola told reporters on Tuesday. "We will see in the next days but tomorrow he is not available."
Man City can move one point clear of title rivals Liverpool at the top of the table heading into their final three games of the season with victory over United.
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