Viktor Gyokeres' proposed move to Arsenal could fall through, according to reports from Portuguese media.
However, MailSport understands that Sporting were hoping to drive up the player's price but Gyokeres still has his sights set on joining the Gunners.
According to Portuguese outlet Record, there is a disagreement regarding bonuses being offered to the player.
Sporting are said to be demanding €10million, which Arsenal are allegedly reluctant to include on top of a £62.4million transfer fee.
The report goes on to claim that, while all scenarios are still open, there is 'a serious risk that negotiations will collapse completely'.