The former Bafana Bafana international had been training with The Brazilians in the hope of impressing Neeskens and ending his long search for a new club.
But Sundowns communications manager Alex Shakoane has told SuperSport.com that the 28-year-old has now been told he can seek employment elsewhere.
“We have released him, he is no longer training with us. The coach felt he was not what we needed,” Shakoane says.
Van Heerden’s business manager, Rob Moore, said there was “no news” on where to next for the attacking midfielder.
Van Heerden has not played competitive football since February having fallen out of favour with Belgian club Westerlo.
His contract with the team expired at the end of last season and he has been looking for a side ever since, having trials in Portugal and training with Lierse in Belgium too to keep fit.
He has been linked with moves to Orlando Pirates and SuperSport United in the last nine months, but as of now he is still on the hunt.
Being a free agent, he is free to join any PSL or overseas side outside of the transfer window.