The Portugal international, 34, has signed a contract with the Rio de Janeiro-based club until the end of 2013 following the expiry of his deal with Corinthians, whom he joined in January 2011.
Flamengo are yet to confirm the deal as they are reportedly waiting to receive the green light from the club's medical department before announcing the player.
Liedson has struggled for fitness and form since undergoing knee surgery last year, scoring four goals in 28 appearances this season after an impressive start to his second spell at Corinthians.
According to Globoesporte, the former Sporting Lisbon striker will be officially unveiled by Flamengo on Friday if he passes a medical.
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