In November 1969 he was part of a five-player trade that sent him to the Cincinnati Reds. He proved to be one of the most effective and durable relievers in baseball for the Big Red Machine; he was in the top five in the National League in games pitched in six consecutive seasons from 1972 to 1977. He pitched at least 121 innings in each of those six seasons, and was part of a tandem of reliable Reds relievers along with Clay Carroll (who was with the Reds through the 1976 season). No National League pitcher appeared in more games from 1970 to 1978 than Borbón. Borbón and Carroll, along with relievers Wayne Granger, Will McEnaney, and Rawly Eastwick, anchored a bullpen that enabled Reds manager Sparky Anderson to change pitchers frequently, earning him the nickname "Captain Hook."