Holmes was selected by Pittsburgh Steelers in the eighth round of the 1971 NFL Draft. He was part of the legendary Steel Curtain defense along with fellow linemen Joe Greene, Dwight White, and L. C. Greenwood. While quarterback sacks were not an official NFL statistic until 1982, the Steelers credit Holmes with a career total of 40, eighth on the franchise's all-time list. This includes team-high totals of 11 in 1974 (including a stretch of six consecutive games with a sack, which ties him with Greene and Greg Lloyd for the longest such streak in team history) and 10.5 in 1975.