Born in San Lorenzo in Zulia, Herrera was signed by the Houston Colt .45s in 1964 as an amateur free agent and made his debut with the team on June 3, 1967, two years after it became the Astros.

It was an unusual debut: Houston third baseman Bob Aspromonte, facing future Baseball Hall of Famer Jim Bunning of the Philadelphia Phillies in the fifth inning, protested a strike two call and was ejected from the game by umpire Frank Secory; Herrera, called upon to pinch hit with a two-strike count already on him, struck out—with the "K" charged to Aspromonte.

After hitting .301 in Triple-A, he appeared in 47 games for Montreal from June 17 through the end of the season, including 31 starts as an outfielder.

He got off the mark quickly, batting over .350 into mid-August, and was still hitting .323 on September 1 with 11 multi-hit games, and his first two big-league home runs, struck July 24 and 26 against the Atlanta Braves at Fulton County Stadium.

Herrera had only one at bat on Opening Day 1970 at Crosley Field, Cincinnati, as a pinch hitter and struck out in his final MLB appearance.