Cristiano Ronaldo leaves Portugal training session with iced knee

Portugal's Cristiano Ronaldo and Pepe, back, arrive for a training session, in Campinas, Brazil, Thursday, June 12, 2014. Portugal plays in group G of the Brazil 2014 soccer World Cup. (AP Photo/Paulo Duarte)

CAMPINAS, Brazil -- Cristiano Ronaldo cut short a training session with Portugal on Thursday, leaving the field with an ice pack over his left knee -- indicating that his tendinitis may still be bothering the star forward.

Ronaldo trained with the rest of the team for about 15-20 minutes doing physical exercises but then did not take part in the rest of the session with full ball drills.

Instead, he stretched on his own and signed a few shirts for fans before going to sit on the bench. When he left, he had an ice pack over his left knee.

Ronaldo has been bothered by left leg injuries ahead of the World Cup, and was sidelined for two weeks with tendinitis in the knee and a thigh problem.