Mkhuma was promoted to the senior team on the last day of the transfer window after captaining the club's MDC side this season.
The Brazilians youngster was earlier linked with a move to Maritzburg United before signing a senior team contract on Friday.
Mosimane says the free-kick specialist will go through the same development stages the likes of Percy Tau went through at Sundowns before they became successful.
"Promise has done very well. He has proved that he deserves my attention," said Mosimane.
"He has really shown that I must look at him. The free-kicks have been good and he has been supplying the balls.
"Let's put him in. Let's stress him and see how he handles this. It's a little difficult, you know the story.
"You park him a little bit somewhere like Pitso [Mkhulisi], like we did with [Motjeka] Madisha, like we did with Percy Tau, and we can bring him [into the senior squad] a little bit later.
"Let's see first what Promise can do."