Sirino, who has adjusted quickly to life in Africa after making a move from Bolivia in January, is suspended for the Group C clash against Togolese outfit AS Togo-Port next week.
Sirino scored from the penalty spot in Sundowns’ last game against Horoya, which ended 2-2 in Conakry, but he also picked up a booking which rules him out for the upcoming game.
He will be missed by Sundowns, but the likes of Sibusiso Vilakazi and Themba Zwane can help inspire the Absa Premiership champions to a much-needed victory.
“Yes, Gaston is not with us. He is suspended for this one,” coach Pitso Mosimane told KickOff.com.
Sirino is not the only one missing for the clash against Togo-Port. Percy Tau did not travel with the team as he looks to finally get his move to the English Premier League concluded.
Tau, who has attracted interest from Brighton Hove & Albion, has not been with Sundowns during pre-season.
Sundowns, meanwhile, have travelled with the likes of Cuthbert Malajila, Anthony Laffor and Aubrey Ngoma, who is looking to finally make his mark having struggled with injury since joining the club in January.
New signing Andile Jali is also part of the squad as he has been registered for the Champions League. The former Orlando Pirates man will add value as Sundowns look to reclaim the title Wydad Casablanca stole from them last year.