The United Arab Emirates-based Gyan is suffering from a tendon problem in his knee which has cast doubt on his participation in the January 21-February 12 event being co-hosted by Gabon and Equatorial Guinea.
Ghana, finalists in Angola in 2010 and hosts in 2008, are one of the favourites to win the continental crown they last claimed in 1982.
Gyan's setback has ruled him out of playing for the next two weeks but in a bid to speed up his recovery a Serbian specialist is being flown out to the Black Stars' training camp in South Africa.
Ghana arrived in South Africa on Saturday to put the final preparations to their Nations assault where they are drawn in Group D in the Gabon city of Franceville, with Guinea, Mali and Botswana.
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