The Black Cats boss is eager to bring in more attacking firepower, with a centre-back also high on the agenda.

Talks have been ongoing with Aston Villa regarding striker Ross McCormack, but the 30-year-old's bumper wages mean negotiations are complex.

That reflects the wider picture in the market, as the Black Cats look to add quality to their squad but with deals that do not risk the club's already difficult financial situation.

Grayson said: "Certain players are on big contracts and their clubs are not going to loan them out or sell them to the first team that comes along – they might wait until later in the window because someone else might come in from another club.

"We've done the deals that we have done so far because it has been right for the clubs that we have got them from, but some of the deals we have been asking about are not quite right for other clubs at this moment in time.

"It's going to be a case of showing some patience, and not diving in when we don't need to," he added.