Four players have been axed from the provisional 27-man squad named by manager Sebastian Migne among them Sweden-based winger Christopher Mbamba, Anthony Akumu, former Golden Arrows winger Clifton Miheso and Onyango.
The towering defender who's based in South Africa is said to have picked up a long-term knee injury in their morning training session on Tuesday and has subsequently been ruled out.
Tottenham Hotspur midfielder Victor Wanyama will lead the side after an excellent season with the Premier League side, in which they reached the UEFA Champions League final.