Switzerland striker Josip Drmic will miss Euro 2016 after undergoing surgery on a knee injury.
The 23-year-old came on as a substitute during Hamburg's 1-0 defeat to Bayer Leverkusen on Sunday and sustained cartilage damage.
The club confirmed the diagnosis on Tuesday, adding in a statement: "The Swiss must be operated on and will be out for the rest of the season".
Drmic, who is on loan from Borussia Monchengladbach until June and has subsequently played what will likely be his last game for Hamburg, vowed to battle back to fitness as soon as possible.
Writing to fans on his official Facebook account, he said: "You may think it is difficult for me to be as optimistic as you. But I've always been a fighter and will take on this fight and return as soon as possible."
Switzerland's official team Twitter account later ruled Drmic out of contention for Euro 2016, saying: "How bitter! Josip Drmic needs surgery on his knee and misses Euro 2016."
Drmic has scored once in six Bundesliga games since leaving Gladbach for Hamburg during the recent transfer window.
He scored four goals during Switzerland's successful qualifying campaign for the finals in France, including two in the crucial 3-2 victory over Slovenia, in which Vladimir Petkovic's side came from two goals down in the final 10 minutes.