The winger, who has 44 caps for Ghana, has recovered from a minor thigh injury he picked up in training with Marseille 10 days ago.
Ayew, the 23-year-old son of former Ghana great Abedi Pele, was due to join his national squad last weekend for the medical staff to assess his injury, but he did not show up on time, prompting coach Kwesi Appiah to drop him for the tournament.
Forward Morgan Amalfitano and versatile defender Lucas Mendes, who both missed the French Cup win over Guingamp last weekend, are also available again for third-placed Marseille.
Like Ayew, Togo goalkeeper Kossi Agassa is expected to feature for Stade Reims on Sunday despite having been ruled out of the African Nations Cup because of a knee injury.
Midfielder Odair Fortes, who withdrew from his national team, Cape Verde, with a knee injury, has also made 16th-placed Reims' squad for their home game against Bastia.
The African Nations Cup takes place in South Africa from January 19.