Updated

Brazil's Workers' Party on Tuesday replaced jailed former President Luiz Inacio Lula da Silva as its candidate for October's general election, clarifying one of the biggest question marks hanging over the vote to lead Latin America's largest nation.

The party confirmed the move after a meeting of its executive committee in the southern city Curitiba, where da Silva is jailed. Fernando Haddad, a former Sao Paulo mayor, will lead the ticket and be joined by Manuela D'Avila, a member of Brazil's Communist Party.

The move, while long expected, was an acknowledgement that the party could not get da Silva, who Brazilians universally call Lula, on the ballot despite numerous attempts in the courts.

"The struggle has just begun. Let's go, Haddad! Haddad is Lula!" the Workers' Party Twitter account said. "He was a Lula minister, he is a Lula attorney and best of all: he is a friend of Lula's."

The political science professor turned education minister and later politician was meeting with da Silva Tuesday after the decision, members of the left-leaning party said. A press conference and formal announcement were expected later in the afternoon.

Da Silva is serving a 12-year sentence for trading favors with construction company Grupo OAS for the promise of a beachfront apartment. The former president, who governed between 2003 and 2010, has always denied wrongdoing, arguing this case and several others pending against him are meant to keep him off the ballot.

Lula led polls for more than a year, but his candidacy was recently barred by the country's top electoral court.

Recent polls show Haddad far behind, but the party hopes he will now rise with da Silva's endorsement. The current leader is far-right congressman Jair Bolsonaro, consistently over 20 percent in a race that puts several candidates at around 10 percent.

Haddad was education minister under da Silva and his successor, Dilma Rousseff. In 2012 he was elected mayor of Sao Paulo, the most populous city in South America, but failed to get re-elected four years later.

A Datafolha poll published on Monday shows Haddad in fourth place, favored by 9 percent. That was a rise of five percentage points in just a few weeks, but still behind Bolsonaro's 24, left-leaning Ciro Gomes' 13, centrist Marina Silva's 11 and right-leaning Geraldo Alckmin's 10 percent.

The poll had a margin of error of 2 percentage points. All the 2,804 voters sampled were interviewed on Monday, days after da Silva's candidacy was barred by the electoral court and Bolsonaro was stabbed in an incident that might put him in hospital until election day.

If no candidate gets more than 50 percent on Oct. 7, a runoff will be held on Oct. 28.

Political science professor Alberto Almeida, who has written several books on Brazilian polls, believes Haddad has a lot of potential to gain popularity, despite the little time for his campaign.

"By next week, it is possible that Haddad grows enough to see Marina and Ciro behind him. That was predictable because of Lula's high support at around 40 percent in the polls," Almeida said, adding: "The race is clearer now."