The 23-year-old has been in scintillating form for the Brazilians this season, and reports suggest that this could be his final few months in the PSL.
While the Tshwane giants have already made peace with the fact that Khama Billiat is leaving the club, it remains to be seen if they will cash in on Tau whose contract expires in June 2019.
Tau attracted interest from Russian club FC Rostov and Danish outfit Midtjylland in January 2018, but Sundowns decided to hold on to him for the second half of the season.
His agent, Mmatsatsi Sefalafala confirmed at the time that the two clubs had shown interest, and in addition, an offer believed to be around R18 million was on the table for the young attacker.
Now given the latest developments, it's unclear if any of the abovementioned clubs will be willing to match Sundowns' asking price or come even closer to matching it come July.
In recent years, Sundowns have appeared reluctant to sell their star players to European clubs, and given Pitso Mosimane's statements that Tau should stay in the PSL for at least another season before considering a move to Europe, chances are that Tau could find himself playing in South Africa for another season.
A few years ago, the club lost Bongani Zungu to Portuguese outfit Victoria Guimaraes for free after Sundowns refused to sell him despite the player approaching the end of his contract with them.
If Sundowns don't cash in on Tau this year, chances are that he will also leave for free come next year provided he doesn't sign a new contract with the former African champions in the near future.
The South Africa international has directly been involved in 26 goals for Sundowns this season - 11 goals and 15 assists.