The 25-year-old was injured during Sunday's 1-0 loss away to Athletic Bilbao and underwent a scan today.
"According to the MRI that was undertaken this morning on Victor Ruiz, the player has a hamstring injury in his right leg," the club said.
"The estimated period of recovery is approximately one month."
The news gives coach Ernesto Valverde a real headache ahead of the weekend meeting with Real Betis as fellow defenders Adil Rami and Ricardo Costa are already sidelined.
Click here for completely free £10 bet with Sky Bet & £5 free every week


 





