Crystal Palace could reportedly end up spending £8.5m on Peterborough United centre-forward Dwight Gayle.
The two clubs are believed to have agreed a fee for the 22-year-old, with some speculation claiming that the figure is around £6m.
However, depending on success, the Eagles may have to part with a further £2.5m under the terms of the deal, according to The Sun.
It has also been suggested that League One outfit Peterborough have insisted that they should receive 25% of any sell-on fee.
Gayle is reported to have settled on a four-year contract at Selhurst Park worth around £18,000 per week.
