Real Sociedad expected to secure the signing of Umar Sadiq but talks with Almería have stalled.
The parties were close to reaching an agreement but the operation has taken a last-minute turn that could scupper the deal.
The operation for the departure of the Nigerian striker was on track for €20m plus €5m in add-ons, according to AS, but it has been stopped by figures that do not convince Real Sociedad.
Several people in the negotiation even considered the deal to be closed while waiting for the definitive yes from Turki Al-Sheikh, the owner of Almería.
Al-Sheikh, who has a reputation for being eccentric and unpredictable, has put the brakes on the deal and at the time of writing, the operation is in serious danger of not going ahead.
On Tuesday night La Real expected to finalise an agreement with Almería, but nobody expected Almeria to pull out of the negotiations in this way. Sadiq trained with Almería on Wednesday.