Atletico Madrid striker Diego Forlan is expected to be sidelined for four weeks with a thigh injury.
Forlan suffered the injury during Atletico’s 3-0 win over PSV Eindhoven in Tuesday’s Champions League opening group game.
The Uruguayan was replaced just after the half-hour mark by Florent Sinama-Pongolle and tests have show there is a tear to his thigh muscle.
“We do not have complete happiness because of the injury to Diego Forlan,” Aguirre told reporters after Atletico’s win.
“He came back from Uruguay and has suffered bad luck. Hopefully he can recover soon because he is an important player for the team.”