Liverpool defender Dejan Lovren has suffered a torn abdominal muscle, according to the Croatian Football Federation.
The centre-half has withdrawn from his country's squad for European Qualifiers against Bulgaria and Azerbaijan after pulling out of a training session.
And a statement on the Croatian Football Federation website read: "During training on Wednesday, Lovren felt pain in the abdominal wall.
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"Igor Boric (a specialist) at St Catherine Hospital showed there was a tear and he will not be ready for performances in Sofia and Osijek."
Lovren is now set to return to Liverpool for further assessment and there is no indication yet whether he stands to miss any club matches.
Liverpool have been without Daniel Sturridge for seven matches because of a thigh problem suffered when he was away with England, while Emre Can and Joe Allen are also out having been injured on international duty.
Any absence for Lovren would leave Brendan Rodgers with just two fit central defenders, Martin Skrtel and Kolo Toure, as Mahmadou Sakho recovers from a thigh injury.
The Reds return to action on Sunday 19 October when they travel to Loftus Road to face QPR in the Premier League, in a game to be shown live on Sky Sports.