The Brazilian playmaker was stretchered off shortly after the hour mark of his country's World Cup qualifying stalemate with Colombia on Wednesday.
Hughes: "We are still waiting for real definite news.
"But we have yet to hear from their medical department so we take the view that he is fit and well.
"We have looked at the tape and seen the incident when he had to come off.
"From looking at those pictures it doesn't look a significant injury, so we expect him to be fit when he returns."
Jonas Gutierrez: "Robinho is just one player, and one player does not make a team.
"He is a world-class performer. But we have to focus on our big-name players. We can't stand in awe of one player.
"I hope I will be fit for Manchester City. If not, I definitely expect to be back for Sunderland.
"I loved working with Kevin Keegan, but working with Joe Kinnear is also good. He is different, but in a good way.
"Now I just want to get back playing again after my injury."