The Chelsea loanee, who has netted four times in all competitions, limped off during Stoke's 1-1 Premier League draw at West Ham on Saturday after pulling up when attempting a shot.
"It looks like Victor has pulled his hamstring," said Welshman Hughes.
"It looks like it is in a strange position as it seems to be right behind his knee, which isn't the normal position you usually get hamstring injuries.
"We will get it checked, it may be something that isn't to do with the hamstring so it could be that we get good news but we can't be sure yet.
"If it is a hamstring, then it could be that we lose him for a few weeks."
Stoke also lost defender Marc Wilson at half-time, with the Irishman failing to overcome a knock to the hip.
"Marc got a bang right on his hip, fair play to him he tried to go out for the second half and see if he could make it work," added Hughes.
"Sadly he couldn't loosen it off and had to be forced off unfortunately."
