Sunderland boss Steve Bruce admits he may be forced to scrap his efforts to sign Darren Bent.
The Black Cats have been chasing the Tottenham Hotspur striker for some time and had hoped to have made positive progress in their endeavours by now.
However, a deal remains some way off and Bruce has revealed that he is running out of patience.
Spurs' seemingly imminent capture of Portsmouth frontman Peter Crouch could help to speed up proceedings, but the signs do not look good.
"I do not know if Tottenham's deal for Peter Crouch will help us. It is one we are visiting, but we cannot wait around forever," Bruce said in the Sunderland Echo.
"We are still short, a long way off in terms of our valuations at the moment. We will look at it again, but if we can't agree, we will move on.
"We are not making headway at the moment and there hasn't been any progress over the weekend."
Bruce has already landed Fraizer Campbell, Paulo Da Silva and Lorik Cana this summer, and admits to being happy with the business he has completed, but he accepts that he may be forced to look elsewhere for further attacking reinforcements.
He said: "We have three players there who have chosen Sunderland ahead of other clubs, so I'm very happy with our ability to attract very good players.
"There are four or five weeks to go before the transfer window closes and, while you can't wait and wait for the people you want, we will not be impulsive.
"We are trying not to make any mistakes in the market and I haven't wavered too much from the people I want to get in, but that might have to change."