Environmentalist Marina Silva will join the race for president as Brazil's Socialist Party candidate.
The candidate who began the election cycle as the running mate of Eduardo Campos made the announcement on Wednesday, a week after Campos died in a plane crash.
Beto Albuquerque, who heads the party in Brazil's House of Representatives, will be Silva's running mate.
Campos was polling a distant third behind Brazil's President Dilma Rousseff of the Workers Party and the centrist candidate, Aecio Neves. However, polls since Campos' death show Silva running about even with Neves.
Many political analysts say Silva may be a stronger candidate than Campos. They say she might at least thwart a first-round victory for Rousseff on October 5.
Silva’s main support comes from Brazilians unhappy with sluggish economic growth, high taxes and poor health care and education.