Sunderland says Gyan will remain with Al Ain after moving there on loan in September last year. The English Premier League team didn't disclose any more details of the transfer of the 26-year-old forward.
Gyan made 37 appearances and scored 11 goals for Sunderland after joining following the World Cup in South Africa in 2010, when Ghana reached the quarterfinals.
He took an indefinite break from international football this year after missing a penalty in Ghana's semifinal loss to Zambia at the African Cup. It was the second time he missed a crucial spot kick for his country.
His miss against Uruguay at the World Cup denied Ghana a place in the last four.