The 31-year-old Bleoobi (Old Student of Accra Academy) has teamed up with the Turkish Super Lig side get himself in top shape for the new campaign.
Gyan signed a two-year deal early this month but was given extended holidays after featuring international matches.
Kayserispor will start their campaign against giants Galatasaray away on 12 August.
The super star recently received a doctorate degree and also unveiled an Astro turf for his alma mater in Accra.
By Sammy Heywood Okine