Mosimane voiced his displeasure after Khama Billiat - who recently switched allegiance from Sundowns to Kaizer Chiefs - won the award in the clubs' 1-1 draw at Loftus Versfeld on Saturday.
The winner of the accolade is decided by TV commentators.
"I thought it was the voting again," Mosimane said at the post-match press conference in Tshwane.
"You know Chiefs has many supporters. So when you vote they will out-vote everybody. I thought it was this sms again, like the Shell Cup. I saw people voting for Man of the Match. I mean really. But it's okay, I respect."
He continued: "Who chooses the Man of the Match? Don't you want to ask him the question? How do you choose? Maybe you [journalists] can help us.
"The ghost who chooses the Man of the Match. I mean which angle does he come from?"
Downs tonight visit Polokwane City at Peter Mokaba Stadium in their second league match of the season.