Barreto was optioned to Triple-A Nasville on Saturday.
The need for Barreto has become minimal since Marcus Semien returned from the disabled list earlier this week, so the team will send him down to get more regular playing time. Recognized as one of the top prospects in the Oakland system, the 21-year-old hit just .190 over 42 big league at-bats, but received some valuable experience and could certainly return for a late-season stint. He heads back to Triple-A for now, where he was slashing .281/.326/.428 with 32 RBI before being called up.