Following the conclusion of the 2016/17 Premier Soccer League (PSL) campaign, Castro returned to South America to attend to his pregnant wife.
The club returned for a pre-season training camp in Rustenburg this week after a three-week break without Castro.
Nonetheless, Goal can confirm that the 28-year-old will only return once his child is born.
“Yes, he is not back yet as he supporting his wife who will give birth. He will only return after the wife gives birth,” Sundowns’ spokesman, Thulani Thuswa told Goal.
The uncertainty surrounding Castro’s return could possibly pose a concern for Pitso Mosimane and his technical team as they begin their 2017/18 campaign with an MTN 8 encounter against Maritzburg United next weekend.
The Tshwane giants are admittingly a bit short on striking options, and Castro’s absence could once again force Mosimane to utilise Percy Tau a false nine; a tactic which was utilised effectively due to Castro’s injury woes last season.