In 2002, he was loaned to A.C. Milan where he was part of the Allievi Nazionale side that won that year's Torneo Città di Arco [it], defeating Fiorentina in the final.
Barreto spent the 2008–09 season on loan at Bari,[3] with whom he scored his first hat-trick in Serie B on 21 April 2009 during a match with Ancona.
However, after the injury of centre-back Andrea Ranocchia and his striking partner Vitaly Kutuzov, the team performance also slipped.
[4][5] In the next season, despite Kutuzov was recovered from injury, the team saw the departures of Italian international centre-backs Andrea Ranocchia and Leonardo Bonucci.
With the failure to sign important replacements, not only for the centre-backs, the team conceded more goals and their tactics where affected.