According to coach Pitso Mosimane, Sirino has a toothache and has a slight calf problem after he was tackled by Free State Stars right-back Nyiko Mobbie at Loftus Stadium on Wednesday night.
Sundowns will certainly need their influential Uruguayan when they face off with the Buccaneers on Saturday. He has been one of their main creative sources and has found his scoring boots for the defending league champions.
Sirino did not take part in Sundowns' training on Thursday morning and a decision on whether to include him in the team to face the Soweto giants is likely to be made today.
“Gaston has an unbelievable toothache and he was also kicked on the calf,” the former Bafana Bafana coach said.
Another player who Sundowns need to make a decision on is central defender Ricardo Nascimento.
“He’s got a groin. It’s disturbing. We’ll see tomorrow [Friday]. Fortunately Anele [Ngcongca] is back, Anthony Laffor trained yesterday. I have not seen him in boots for a long time, it’s unbelievable,” said Mosimane.