Mthethwa is due to start training with Dikwena this afternoon after penning a three-year contract with the Premiership club.
Striker Mabena and midfielders Tshabalala and Mathe have left the team following the expiry of their contracts on June 30.
"It's a done deal with Sbu," says a club official.
"We will make an announcement soon about players leaving the club," he adds, with a further three players expected to depart the Rustenburg-based outfit.
Stars have also just roped in former Baroka co-coach Milton Dlamini to assist new head coach Peter Butler, while they have their eye on in-demand Mamelodi Sundowns goalkeeper Thela Ngobeni.