The 26-year-old joins the club on a free transfer after leaving South African giants Pirates midway through the current 2016/17 campaign.
"Edwin is a top player. He is overqualified for the league but he shall serve them on a short term and then move on to a bigger platform," Ryan Hartslief, Gyimah's agent, said.
Gyimah spent five years in the PSL playing for SuperSport United, Mpumalanga Black Aces and Pirates.
His stay in the PSL saw him make 123 appearances in all competitions for all three clubs and scoring only two goals.