Giorgos Samaras will be out of action for at least a month after sustaining an arm injury playing for Greece against Latvia on Friday night.
Medical tests showed that the 27-year-old Celtic striker suffered ligament damage in his left arm during the 2-1 win in the World Cup qualifier.
Team doctors expect Samaras will need four to five weeks to fully recover and be able to play again although he will undergo further tests on Sunday before rejoining the Hoops on Monday.
Samaras, a doubtful starter due to a previous back injury, was used by coach Fernando Santos in the second half for 22 minutes as a substitute and with Greece down 1-0 at the time.
Although he helped turn the match around with his performance the game ended in personal disappointment as he will miss Greece's next qualifier at home to Lithuania.
More significantly for Celtic fans, Samaras will also miss the opening games of Celtic's Champions League campaign.
Greece team-mate Fanis Gekas, who scored the winner on Friday, has hailed the impact of the stricken Samaras.
"Giorgos is a fantastic player. In the match with Latvia he came in during the second half and showed that he is in top form," said Gekas.
