As well as John Oster, City have been linked with a couple of other players this week.
Brighton full back Dan Harding is a potential target
"We have an interest and are monitoring his progress, but no approach has been made yet," said Lennie Lawrence.
Other names mentioned are Hibernian's Derek Riordan and Icelandic midfielder Gylfi Einarsson.
Cardiff's next match is six pointer against Rotherham at Ninian Park a week tomorrow.