The bulky forward left the West African country on Friday evening together with his manager.
He will undergo his mandatory medical today before his official unveiling by the club later today.
The 20-year-old, who scored 12 goals in 32 appearances for Faisal in the just-ended football season.
Peprah will sign a long-term contract with Pirates if he passes medicals and is able to reach personal terms with the Houghton-based club.
The striker became a subject of transfer interest for Kotoko, Hearts of Oak, Dreams FC and Medeama a month ago.
King Faisal, the Ghana Premier League club that owns the economic rights of the player for the time being, turned down an offer North Macedonian club FC Shkupi who proposed a 15,000 Euro loan deal.