Dinamo Zagreb midfielder Arijan Ademi has been handed a four-year ban by UEFA after failing a doping test, the Croatian club have announced.
The 24-year-old Macedonia international failed a routine drugs test following Dinamo's 2-1 Champions League victory over Arsenal in September, a match in which he played the full 90 minutes.
Dinamo confirmed last month that Ademi had also returned a positive test for his 'B' sample and on Friday the club announced he had been banned for four years.
The reigning Croatian champions also said they were "shocked" by the ruling, with Ademi - who also played in the 5-0 defeat at Bayern Munich on September 29 - insisting he has done nothing wrong.
A club statement on www.gnkdinamo.hr read: " The disciplinary committee of UEFA decided to suspend Arijan Ademi for four years.
"After Ademi had been provisionally suspended for failing a doping test after the Champions League win over Arsenal in September, UEFA decided to suspend him for a long period.
"GNK Dinamo are shocked with UEFA's final decision. The club will do everything in order to help Ademi in this tough situation."
Ademi said: " I can't describe how I feel right now. I am not guilty and I didn't do anything wrong. I don't know what to say about this suspension... I feel awful right now.
"I would like to thank all people for their support, but this is a really tough moment for me so I hope you all understand me."
Dinamo head coach Zoran Mamic said his club would protest the decision, which he described as a "humiliation".
He was quoted as saying by his club's website following Dinamo's 2-1 win over Slaven Koprivnica on Friday night: "Ademi and experts proved his supplement was infected with a prohibited substance and he didn't know what kind of supplement he was using. That is why I can't understand this decision made by UEFA.
"We should all be very careful because there are strict rules about doping in football, but a four-year suspension is a stupidity. How would UEFA punish Arsenal, Bayern, Manchester or some other big club? This is humiliation of all of us.
"We will make a complaint about this decision and we are all shocked. We will fight for him and for his case because Ademi is a brilliant young guy, player and a vice-captain. We want to protect him, protect the club and Croatian football in general, because this is a huge stain for all of us."