Former special forces general Prabowo Subianto said Monday he was asked by President Joko Widodo to join the Cabinet, which will be announced Wednesday.
Subianto declined to say if he had been asked to become defense minister as widely speculated by local media.
Widodo, who was sworn in for his second term on Sunday, said Indonesians should unite after the bitter election campaign.
Subianto had refused to accept the April 17 election results. He alleged massive and systematic fraud, but his legal challenge was rejected by Indonesia's top court last month.
Nine people died in riots in May after official results showed that Widodo had won 55.5% of the vote.