French forward David Trezeguet is to have an operation on his troublesome knee on Tuesday and faces up to five months on the sidelines, his club Juventus said.
Trezeguet, who missed the start of the season because of another knee problem, injured the same knee in Wednesday's UEFA Champions League match against Zenit St Petersburg and missed Sunday's 1-0 victory at Cagliari.
But the club claimed on Monday that despite previous reports the new injury has nothing to do with the tendon problem he had at the start of the season.
"It's something new which has nothing to do with the tendon issue," said a club statement. "The recovery time will be a minimum of three months and a maximum of four to five."
Trezeguet joined the Italian giants from Monaco in 2000 and scored 20 goals in 36 matches last season to finish second behind team-mate Alessandro Del Piero in the scoring charts.
In July, the 30-year-old retired from international football after the news that Raymond Domenech - with whom he has a strained relationship - was to stay on as national coach.