BRASILIA (Reuters) - Former Sao Paulo mayor Fernando Haddad will be the Brazilian leftist Workers Party’s presidential candidate if jailed former President Luiz Inacio Lula da Silva is barred from running in the October vote, a party source said on Friday.

FILE PHOTO: Former Brazilian President Luiz Inacio Lula da Silva speaks at his book launch event in Sao Paulo, Brazil March 16, 2018. REUTERS/Paulo Whitaker/File Photo

If Lula is able to run, Communist Party hopeful Manuela D’Avila is likely to abandon her own bid for top office and instead become his vice presidential running mate, according to the source, who is close to the negotiations and asked for anonymity.

But later on Friday, the head of the Workers Party, Gleisi Hoffmann, said after visiting Lula in the federal police building in Curitiba where he is incarcerated that the former president had asked for a few more days for the party to decide about the running mate name.

Neither Haddad nor D’Avila could immediately be reached for comment.

The 72-year-old Lula leads opinion polls in Brazil’s most uncertain race in decades, despite his slim chance of actually being able to run.

The Workers Party has said it plans to nominate Lula at its convention on Saturday, even though he cannot actively campaign as long as he is in prison, and will almost certainly be barred from running in the Oct. 7 election, due to a corruption conviction.

The choice of Haddad suggests party officials are coming around to the idea of transferring Lula’s support rather than having him mount his own campaign from jail.

Haddad, 55, of Lebanese-Christian descent, lost his 2016 bid for re-election to Sao Paulo’s city hall in a stunning first round defeat to rising conservative star Joao Doria.

Haddad’s relative youth and distance from the major corruption scandals roiling Brazilian politics had bolstered expectations that he could be the most likely stand-in for Lula. Still, his resounding 2016 defeat and lack of a connection with the party’s northeastern base has counted against him.

Despite running for the presidency, D’Avila and her Communist Party of Brazil were widely expected to eventually join forces with the Workers Party.

On Thursday, Brazilian Senator Ana Amelia Lemos said centrist presidential candidate Geraldo Alckmin was close to confirming her as his running mate.

The pick may help Alckmin target a weakness of rival candidate and right-wing congressman Jair Bolsonaro, the opinion poll front-runner if Lula is excluded. Bolsonaro has made comments denigrating women and his backing among women is half that of his support from men.