In a frank radio interview, Shivambu said the league had assessed Zuma's performance and that he had failed to implement mandates as adopted in Polokwane in 2007.
"I doubt that he will be re-elected. Actually, I'm not even doubting. I know he will not be re-elected as a president of the ANC at the 53rd national conference," Shivambu told 702 talk show host Redi Tlhabi.
The league was instrumental in driving Zuma's rise to topple former president Thabo Mbeki at Polokwane.
Asked if they now regret their unwavering support for Zuma at the time, Shivambu said: "He [Zuma] did not carry out the mandate that was given at 52nd conference. We did not know then . [but] he is not the right person to lead the ANC."
Responding to Shivambu's statement, ANC secretary-general Gwede Mantashe said: "We can only wish him luck in being a prophet. It is such a reckless statement, very much reckless."
Shivambu said the league's leadership was now being persecuted for talking on resolutions adopted in Polokwane in 2007, but that they would fight back without fear.
"People must not purge us and remove us from the ANC because we don't support them."
Shivambu said that though the ANC had called for the leadership debate to be opened only in October, the league was never told not to assess the performance of its leaders.
"The ANC has never said we must not do leadership evaluation. We have a right to do that."
He said that even though the youth league leadership had a sword hanging over its head, he was confident that his suspension and Malema's expulsion would be overturned during the December conference.
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