The 24-year-old suffered the injury in the Europa League draw against Estoril at the end of November and subsequently sat out the Primera Division win against Granada at the weekend.
It has now been confirmed that the Spaniard will be out for three to four weeks, meaning he will not return until after the winter break.
"Vitolo, after undergoing medical tests, has suffered a grade two sprain to his right ankle," read a statement on www.sevillafc.es.
"If there are no complications, he will be out for three to four weeks."
The former Las Palmas forward has scored two goals in 11 league matches so far this season.