Gyan, Ghana's all-time leading scorer, missed the Black Stars surprise 1-0 loss to Kenya in September.
The 32-year-old has played just twice this season for his Turkish club Kayserispor and is yet to score.
Ghana host Sierra Leone on 11 October and travel to Freetown to face the same opponents four days later.
There is still no place on coach Kwesi Appiah's list for the Ayew brothers, Andre and Jordan.
Inter Milan's Kwadwo Asamoah retains his place in the squad after returning to the team for the 1-0 loss to Kenya after a four-year absence.
The Black Stars loss to Kenya means that all four teams in Group F have three points from two matches.