Ms Abbott told Good Morning Britain: “Let me say, having known him for over 40 years, Jeremy is not an anti-Semite now and has never been an anti-Semite, whatever you think of his politics.
“It’s extraordinary that we’re just going to throw him out.
“I don’t know if he will run as an independent, but if he does, he will win.
“He has been MP for Islington North for 40 years, a very hard-working local MP and if he is a candidate he will win.”
Ms Abbott asked if she would support Mr Corbyn to run as an independent, saying: “I couldn’t support him because I’m a Labor MP and we shouldn’t support independents.”
Labour’s National Executive Committee last week backed a proposal from Sir Keir not to support Mr Corbyn in contesting Islington North for Labor in the next election.
The former Labor leader is currently sitting as an independent after losing the whip over an anti-Semitic row.
Mr Corbyn has criticized his successor’s decision to prevent him from standing for Labor.
He called it a “shameful attack on party democracy, party members and natural justice”.
Corbyn accused Sir Keir of launching “an attack on the rights of his own Labor members” and “breaking his pledge to build a united and democratic party that promotes social, economic and climate justice”.
In a hint that he could run as an independent, he added: “I will not be intimidated into silence. I have spent my life fighting for a fairer society on behalf of the people of Islington North, and I do not intend to now to stop. “
If Mr Corbyn were to run as an independent in the seat he has held since 1983, he could present a distracting challenge to Sir Keir at the next general election.
But such a move could also lead to him being expelled from the party he has been a member of for nearly 60 years.
Mr Corbyn remains a member of the Labor Party but has lost the whip meaning he sits in the House of Commons as an independent.
Party rules mean he could lose his membership if he announces he is running against an official Labor candidate.
He was suspended over his response to the damning 2020 Equality and Human Rights Commission report on anti-Semitism in Labour.