Olympiakos striker Kovacevic has heart surgery
The 35-year-old Kovacevic flew to Spain from Greece at the weekend after doctors detected high blood pressure and a narrowing of the arteries, Olympiakos said.
"Olympiakos player Darko Kovacevic underwent a coronary angioplasty in San Sebastian, Spain this morning," the club statement said.
"The outcome of the operation is considered 100 per cent successful. Darko Kovacevic is in a very good condition and if all goes normally he will leave hospital tomorrow (Wednesday)."
Kovacevic, who also played for Lazio, Juventus, Real Sociedad and Sheffield Wednesday, was part of the former Yugoslavia's 1998 World Cup and Euro 2000 squads, scoring 10 goals in 55 matches for his country.