Brazilian website globoesporte.globo.com quotes the 36-year-old's agent, Frank Assuncao, as saying he had signed a pre-contract agreement with the Rio de Janeiro club.

"It's all done," Assuncao was quoted as saying. "We have already signed a pre-contract agreement and agreed upon the details."

Vieri has been without a club since agreeing to end his contract with Atalanta in April.

Last Thursday he announced his retirement from the sport, saying: "I don't want to play anymore and I'm not even tempted to play abroad."

Vieri was twice named Italy's player of the year and won the Serie A title with Juventus in 1997, the Cup Winners' Cup with Lazio in 1999 and the Italian Cup with Inter Milan six years later.

For the national team, Vieri scored 23 goals in 49 appearances.