Crystal Palace winger Wilfried Zaha is keen to leave the club this summer for Arsenal, who have expressed interest in him.
Palace value the Ivory Coast international at up to £80m.
However, with Aaron Wan-Bissaka set to join Manchester United, Palace are reluctant to lose Zaha as well this summer.
United, who sold Zaha back to Palace four years ago, would get 25 per cent of any fee if the player is transferred, unless that clause is renegotiated.
It is understood Arsenal were optimistic they would have the necessary resources to bring in the 26-year-old if they had qualified for next season's Champions League.
Failure to do so has however restricted their budget to around £45m, meaning they would need to raise substantial funds through player sales to temp Palace into doing business for Zaha.
The most realistic way of generating the required finance would be by cashing in on Pierre-Emerick Aubameyang, though the potential implications of parting with last season's top scorer would present a major dilemma for the Gunners.
Another key assets is Uruguay midfielder Lucas Torreira, who arrived at Emirates Stadium from Sampdoria last summer and has been linked with a return to Italy.
But while Arsenal accept every player has a price, they have no intention of letting the 23-year-old go and do not believe he is unhappy, contrary to some reports.
Torreira has been most heavily linked with AC Milan and although they do admire him, he is not a focus of their attention - the Rossoneri know the asking price would be prohibitive and have other targets.
Meanwhile, Arsenal remain in talks with Celtic over the signing of left-back Kieran Tierney, 22, and St Etienne regarding their central defender William Saliba, 18.