Borussia Dortmund teenager Konstantinos Karetsas has suffered a second early season setback when he limped out of their Bundesliga match at Union Berlin with an ankle problem.
The Greek teenager came on in the 62nd minute but was then hit on the right ankle by Union player Rani Khedira while shielding the ball. He went down in pain and hobbled off with the help of team staff.
"We must see whether it is something serious. I feel sorry for the lad who has not been kissed by Lady Luck since being here," coach Niko Kovac said.
Team officials said Karetsas will undergo examinations to determine the nature of the injury. He is set to definitely miss Tuesday's Champions League match at Azerbaijan's Sabah.
It is the second setback for Karetsas since his arrival in Dortmund in summer.
Last month he collapsed with circulatory problems in the Champions League match against Villarreal and missed the following league match against Paderborn.
Dortmund played to a 0-0 draw at Union, their third game overall without a victory.
