Ajax have cooperated with the return of Walker to his homeland Brazil. The contract, which expired in the summer of 2005, has been annulled immediately. Walker will play for Brazilian side Clube Atlético Mineiro.
As a player in Ajax's youth devlopment program, Americo Fronio Walker became world champion with Brazil under 17 in 1999. Walker was the World Cup team's captain. He also added the South-American championship to his palmares in that same year.
In July 2000 he signed a contract with Ajax, after which he made his official debut for Ajax 2 on 17 August 2000. Walker celebrated the national title with Ajax 2 in the league for second teams in 2001 and 2002. Ajax's reserves also made a great impression by advancing to the semi-finals of the national cup in 2002.
Walker played for Ajax's Belgian satelite club Germinal Beerschot Antwerpen during the 2002-2003 season. In the highest Belgian league he played 21 matches with 1 goal.
Since his return to Ajax he played for John van t Schip and Marco van Basten 10 official matches in Ajax 2. Walker himself indicated he no longer saw a prospect in staying with Ajax for a longer period.