His apology was carried Monday by El Nacional newspaper.
The Saturday night fight happened during the third game of the series.
Zambrano struck pitcher Mayckol Guiape, of the rival Caribes de Anzoategui, after teammate Ezequiel Carrera, of the Navegantes del Magallanes, was hit by a pitch.
Zambrano asked forgiveness of Venezuelans and the Caribes organization for the “very embarrassing incident.”
The Venezuelan League of Professional Baseball is investigating.
When Zambrano was in the majors with the Chicago Cubs he was suspended for 30 days in 2011 after a shouting match with teammate Derrek Lee.
YANKEES: Authorities say pitching prospect has been arrested for drunken driving in Tampa, Fla.
Police say 21-year-old Omar Luis Rodriguez was pulled over early Friday morning and charged with driving under the influence. Hillsborough County jail records show he was later released on $500 bail.
BREWERS: Signed veteran utilityman Pete Orr to a minor league contract.
Orr hit .200 with no homers or RBI in 20 at-bats over 15 games last season for the Philadelphia Phillies.
For his career, Orr has hit .257 for Atlanta, Washington and Philadelphia.
REDS: Infielder Chris Nelson and the organization agreed to terms on a minor league contract.
The 28-year-old third baseman played for the Rockies, Yankees and Angels last season, batting a combined .227 with three homers and 24 RBI in 64 games.