The Argentina international has picked up an ankle injury and could be sidelined for up to six months due to the knock
The 23-year-old midfielder forgot to apply the handbrake on his car while filling it with petrol after an individual training session and his ankle then got stuck between the curb and the car as it started rolling.
Banega was immediately taken to the Hospital Nou D’Octubre, where he underwent several tests to determine the extent of the injury.
A CT scan has revealed that he has fractured his tibia and Banega will go under the knife on Monday.
It's not yet exactly known how long the midfielder will be sidelined, but Valencia fear that Banega will be unavailable for six months.