Arsenal are believed to be around £4m short of Real Madrid's valuation of loanee Dani Ceballos if they want to make the deal permanent in January or next summer.
The Gunners were able to snap up the Spain international ahead of Tottenham in July as he sought more regular first-team football after struggling to nail down a regular place at the Bernabeu.
A positive start to his career in north London has already led to calls for the north London club to try to sign Ceballos long-term, but it may require more negotiating in order to strike a deal.
According to Spanish publication El Desmarque, Arsenal are prepared to offer €30m (£26m) for Ceballos. However, Real are said to value the 23-year-old at a minimum of €35m (£30m) and it is suggested the only way for Arsenal to strike a permanent deal is by paying the additional €5m (£4m).
Ceballos is apparently aware that his chances of earning a place in the Real team are slim as long as Zinedine Zidane is coach. El Desmarque notes that his situation could therefore change should Los Blancos opt to part company with the under-pressure Frenchman.
Other recent gossip from Spain claimed that Ceballos personally spoke with Real president Florentino Perez during this month’s international break. The player is said to have told his parent club that if Arsenal want to sign him, he hopes a deal can be reached.
The former Real Betis star, who has played 12 times for the Gunners in all competitions so far this season, is said to be happy under Unai Emery and has supposedly asked Perez to meet with Arsenal officials as soon as January to discuss things.
Real are likely to at least double their money if they do sell Ceballos to Arsenal, or indeed any other suitor, having paid a figure believed to be in region of €14m to buy him in 2017.