The Welsh manager has admitted that he may have to look elsewhere in the final days of the transfer window after seeing deals for the Real Madrid and Tottenham pair halted
The Welshman is keen to add depth to his defence after seeing his side suffer a 5-0 defeat at the hands of Swansea City before they drew 1-1 against Norwich City on Saturday.
Hughes had agreed a fee with Tottenham for the transfer of Dawson, but reports claim that the centre-back failed to agree personal terms with the west London club.
The club have also been linked with a season-long loan deal for veteran Real Madrid defender Carvalho, with Inter goalkeeper Julio Cesar also reportedly a target.
"We will have a look at other options," Hughes told reporters after the draw at Carrow Road.
"There might be something which makes sense from our point of view, from a playing situation and a financial one, so we will have to wait and see."
The Hoops have signed seven players on permanent deals this summer and also added left-back Fabio on loan from Manchester United.