Josip Drmic is set to miss the remainder of the Bundesliga season and this summer's European Championships after injuring his knee at the weekend.
The striker will need surgery to fix the problem and is likely to return to competitive action at the beginning of the 2016/17 season.
After suffering what HSV described as "traumatic cartilage damage", Drmic was understandably disappointed.
The forward said he was "deeply saddened", because he felt there was "a lot going for [him]" during the second half of the season.
Speaking on Facebook, he added: "Now I'll be keeping my fingers crossed tightly for the lads."
Drmic has struggled to hit the heights and standards set during his final season at 1. FC Nürnberg, where his 17 goal haul failed to keep the club in the Bundesliga.
From there, he moved to Leverkusen and struggle to get going; the Swiss managed to find the back of the net just six times in nearly 40 games.
Upon joining Borussia Mönchengladbach, a frustrating Hinrunde followed and now Drmic finds himself on loan at Hamburg.
His performance had taken a turn for the better and he scored one goal in his short time in the north, but that has been cut short by this knee injury.
Can Switzerland cope without Drmic?
Switzerland will now head into the Euros without Drmic, who has scored eight goals in 25 appearances for the national team.
They have been drawn with the hosts, France, as well Albania and Romania. It isn't the hardest group they could have been given, but Drmic's loss will be felt.
The goalscoring burden now falls on Haris Seferovic, though is part of an Eintracht Frankfurt side that are struggling to provide for him.
It is unsurprising then, that head coach Vladimir Petkovic branded it a "bitter blow" and a "great loss" for both club and country when speaking to the football association.