Atletico Madrid have announced Koke suffered a hamstring injury against Eibar on Saturday after the midfielder underwent an MRI scan.
The Spain international was forced off with the problem in the 61st minute and replaced by Argentinian youngster Angel Correa, with Atletico being held by their hosts at the time.
Correa made a swift impact, scoring a fine goal a minute later as Atletico went on to win 2-0 – Fernando Torres adding the second 13 minutes from time.
But Koke’s injury left a sour taste for coach Diego Simeone, who will almost certainly be without the midfielder for Tuesday’s contest at home to Getafe and at Villarreal on Saturday.
The club are yet to reveal how long they expect Koke to be out for.