Sunderland have seen a £10 million bid for Wolves striker Steven Fletcher rejected.
Fletcher, 25, is a long-time target of the Black Cats and it remains to be seen whether Sunderland will return with a fresh bid, although reports have suggested any future bid may include Connor Wickham being loaned to the Midlands club in an attempt to sweeten the deal.
The former Ipswich striker, 19, joined Sunderland for £8 million last summer but found first-team opportunities limited last season and may be interested in a temporary move.
Meanwhile Fletcher is said to be keen to remain in the Premier League following Wolves' relegation, despite comments from Wolves chief Jez Moxey on Monday that said the club will not sell its best players.
Elsewhere Martin O'Neill has confirmed the club have lodged several bids for players.
Speaking to the Sunderland Echo, O'Neill said: "We have made a number of bids for a number of players and we're still waiting to hear back."
With reports from the North West claiming the Black Cats are interested in Blackburn Rovers pair Martin Olsson and Steven N'Zonzi, it's believed the club have now moved to secure their signatures.
"I can't obviously mention particular players, but we're definitely in the market to try to improve the squad." O'Neill added.
So far only Carlos Cuellar has joined the Wearsiders, despite the club being linked with a host of players. Speaking on the subject, O'Neill said: "It's pretty obvious where we're looking to try to strengthen and of course we're going to be linked with a lot of players.