The Ivory Coast Football Federation has confirmed that Yaya Toure is receiving treatment in Qatar for an unspecified injury before joining up with his Ivorian team mates at their World Cup training camp in the United States.
Toure is the only one of the 28 players named in the preliminary squad by coach Sabri Lamouchi to miss the start of their World Cup preparations in Dallas.
In a statement, the federation added that he will only fly to the U.S. next Thursday.
The Aspetar Orthopaedic and Sports Medicine Hospital in Doha confirmed the BBC African Footballer of the Year's admission for what it called, in a statement, a "minor injury".
Toure had suffered a thigh injury in mid-April but returned after two weeks to help Manchester City secure the Premier League title on the last day of the season. He went off in the second half with a reported hamstring injury as City beat West Ham.
Toure's build-up to the June and July World Cup finals in Brazil has been overshadowed this week by comments from his agent Dimitri Seluk who said the midfielder was upset with City after an apparent birthday snub and could leave the English champions.
The Ivorians play two warm-up friendlies in the U.S. against Bosnia in St Louis on 30 May and El Salvador in Dallas on 4 June. They will arrive in Brazil on 6 June.
At the World Cup, the Ivorians have been drawn in Group C and will compete against Colombia, Greece and Japan.