Chelsea are in talks over a deal that could see former striker Didier Drogba return to Stamford Bridge from Chinese club Shanghai Shenhua on loan.
The Ivory Coast international, 34, wants to stay fit to prepare for the 2013 Africa Cup of Nations as the Chinese season has finished.
Drogba has asked Fifa for permission to move outside the transfer window.
Chelsea are short of attacking options with Fernando Torres out of form and Daniel Sturridge injured.
"The Fifa administration services are looking into it," Fifa said in a statement.
Drogba, who has also been linked with Liverpool, spent eight years at Chelsea after arriving from Marseille in 2004.
His last act in a Chelsea shirt was scoring the winning penalty in the Champions League final defeat of Bayern Munich in May.
The striker teamed up with former Chelsea colleague Nicolas Anelka in China in June after agreeing a two-and-a-half-year contract with Shenhua.
He has scored eight goals in 11 games for the Chinese side.
Existing rules prevent Drogba from representing another club until 1 January.
The 2013 Africa Cup of Nations takes place in South Africa between 19 January and 10 February.