Sirino has been out of action for more than a month together with another influential midfielder Themba Zwane, who is still doubtful for the trip to KwaZulu-Natal on Saturday.
The Brazilians lost their last league match against Golden Arrows 3-2 and could use this opportunity to turn the screw against Abafana Bes'thende and seal a place in the final.
Speaking during media day at Chloorkop on Wednesday, Sundowns assistant coach Manqoba Mngqithi admitted his team missed Sirino and Zwane in the last few games.
"It's a blow for us. We lost some key players. The bad part is we lost some offensive players," said Mngqithi.
"Gaston Sirino has been out for a long time but we are hoping he will be back for this one. Mshishi [Zwane] has been out and looks like he will miss this one.
"Everybody knows what Mshishi can do for us but we can't complain and say we are short of players."