Bellamy was forced out of the 1-0 loss at his former club on Sunday with a knee injury in the second half, while Robinho picked up an ankle knock.
Record signing Robinho is expected to miss Wednesday's game against Aston Villa, while Bellamy is due to visit a specialist on Monday.
"Craig will see the knee surgeon that he has seen before, he has a bit of pain on his patella," said Hughes on the club's official website.
"We hope it is nothing serious, we do not anticipate that it will be and it will be checked out on Monday.
"Robbie has gone over on his ankle, it is a similar one to when he was injured against Arsenal, it could be the same injury and he could be out for Wednesday as well."
Richards concernThe City boss also lost Micah Richards after 15 minutes at Upton Park and Hughes is waiting to learn the severity of the defender's hamstring injury.
He added: "Micah had a stiff hamstring yesterday, had some work with the physios last night and it eased off. It was not an actual pull, but he went into a challenge and felt it stiffen up almost immediately.
"We hope we can work on it and release the tightness, hopefully it is not a strain because that would take him out for a number of weeks."