Chacón hit .265 as a reserve second baseman with the 1961 NL champion Cincinnati Reds, starting 34 games during the season.

Immediately after the World Series, on October 10, the 1961 MLB expansion draft to stock the newborn Houston Colt .45s and New York Mets was conducted in Cincinnati.

After he was selected by New York with the fourth overall pick during the draft's regular phase, Chacón was the Mets' first candidate for the 1962 starting shortstop job.

[1] During the 1962 season, New York Mets center fielder Richie Ashburn and Chacón frequently found themselves colliding in the outfield.

He relaxed, positioned himself to catch the ball, and was instead run over by 200-pound left fielder Frank Thomas, who understood no Spanish and had missed a team meeting that proposed using the words "¡La tengo!"