"Vitolo finished the game which we played at Mestalla against Valencia with pain in his left knee," Atletico said in a statement on Tuesday.
"The report from club medics indicates he has suffered a grade two knee sprain."
Although the club did not state the estimated length of Vitolo's absence, this type of injury can take up to a month to heal.
New signing Gelson Martins, who impressed as a substitute against Valencia, may get more playing time in the coming weeks.
(Reporting by Rik Sharma, editing by Ed Osmond)
