According to Sowetanlive, Russian club FC Rostov has already submitted their bid to the Brazilians, with Denmark's Midtjylland also reported to be after the player's signature.
It is now up to the Tshwane giants to either reject both offers or sell their speedy attacker before the January transfer window closes on Wednesday.
Tau's agent, Mmatsatsi Sefalafala confirmed to the publication that it is still a 50/50 situation, before adding that the final decision rests with Sundowns.
"It's a 50/50 situation. I don't know if Sundowns would defer them to the end of the season or allow him to go," Sefalafala said.
"But Percy has a contract with Sundowns and he's still committed to the cause. He will respect whatever decision they make," she added
Pitso Mosimane recently admitted that while he wanted to Tau to eventually go abroad, he didn't think the 23-year-old player was ready for Europe.
Tau's current deal is set to expire in June 2019, and Sundowns could be tempted to cash in on him while he still one of the hottest properties in the South African football.
However, Khama Billiat's contractual situation at Sundowns could also be a determining factor in the future of Tau.
Billiat refused to sign a new contract with Sundowns as he also wants to pursue his football career abroad, and Goal has already reported that the Zimbabwean attacker has an offer from Qarabag FK.
Tau rose to prominence during the club's successful Caf Champions League campaign in 2016, and since then, he has never looked back.
He is Sundowns' leading goalscorer with seven league goals in 19 appearances so far this season.