Bolton Wanderers chairman Ken Anderson has admitted that the club are set to widen their search for a new striker.
The Championship side offer Sunderland's strongest competition for Bradford City's Charlie Wyke.
Both clubs are believed to have made bids for the 25-year-old but as of yet, the League One side are yet to sanction his departure.
Anderson told his club website: "We are still actively looking to recruit several new additions to the squad before then and as ever we shall let you know immediately once the deals have been done and the paperwork completed.
"There has been speculation within the media and social media about our pursuit for strikers, and I can confirm that we have made six-figure bids for two different players.
"At this stage we will not be making any further offers on these players and we shall consequently widen our search."
Wyke is currently injured and will miss the start of the new season.
However, his injury is not serious enough to have deterred Bolton or Sunderland in their pursuit.
Sunderland boss Jack Ross is desperate to add at least one more striker to his ranks, despite completing a season-long loan for Jerome Sinclair on Thursday.
The Black Cats retain an interest in Sheffield United's Billy Sharp, but he is at this stage not expected to leave Bramall Lane.
Bolton boss Phil Parkinson has admitted that his club's search for striking reinforcements had been'frustrating'.
He said: "I’ve never mentioned specific player and people have talked about what is first choice, second choice, but realistically, we need to progress quickly and we need strength in that department.
“In every interview I have done this season I have said the chairman is speaking to other clubs. But unfortunately these things take time. It is frustrating.
“Strikers are hard to get. No-one wants to sell them. But we are working towards sorting it – and I think we need two.”