The 26-year-old right-back was a key member of the Stallions' side as they secured promotion from the Motsepe Foundation Championship through the play-offs last season.
He played four of the club's seven Betway Premiership ties this term as Milford made an impressive start to life in the South African top flight, where they sit in fifth place after eight matches.
Speaking after a 1-1 draw with Durban City last weekend, Pupuma explained that the club support the player's career progression.
“We always knew Ace was going to go; he had a great season last season, so it was just a matter of time,” he said in the Citizen.
"I think against Magesi he had a knock which delayed his preseason and so we had to first sort him out.
"I'm an honest person, so I don't want to create any enemies, so I wouldn't have agreed to let him go with an injury, so we had to sort him out, and we got him back. There are a few others that we were expecting that they would go with the big teams, so we're prepared for that."
"We are not going to hold anyone back, but the offer and the deal have to be good for my player, and I need to see that they are going to look after the boy. Then maybe we'll agree; it doesn't mean we'll agree any time somebody comes and knocks," added the head coach.
