Matija Nastastic could be out for six months after undergoing surgery on a ruptured Achilles sustained in Schalke's win at Werder Bremen.
Schalke's winning start to their Bundesliga campaign at Werder Bremen came at a cost after it was revealed that Matija Nastastic faces a lengthy lay-off with a ruptured Achilles.
The Serbia centre-back lasted just 17 minutes of the impressive 3-0 victory at the Weserstadion on Saturday before limping off and being replaced by Roman Neustadter.
Schalke later stated that Nastastic has undergone surgery, with reports suggesting he could be sidelined for six month.
The Gelsenkirchen club tweeted: "What a blow! Matija #Nastasic has ruptured his Achilles' tendon underwent surgery this evening. Get well soon! #s04."
Nastastic, 22, joined Schalke from Manchester City on a permanent deal in June after a successful loan spell last season.
A Theodor Gebre Selassie own goal and strikes from Klaas-Jan Huntelaar and Jean-Eric Maxim Choupo-Moting ensured Schalke started the Bundesliga in style.