He is now a major injury doubt for the match against West Brom at The Hawthorns on Sunday.
"Robinho wasn't able to continue so he's a big doubt for the weekend," City boss Mark Hughes said after the game.
"It's his ankle again.
"He's made a great impression on everyone in Manchester, scoring eight goals in the Premier League. We're delighted with his impact.
"In the last three games he's been struggling with an injury and that was a concern to him tonight. We're pleased with what he's produced."