Zach Duke, a left-handed pitcher, embarked on his Major League Baseball career with the Pittsburgh Pirates. Drafted by the Pirates in the 20th round of the 2001 MLB Draft, Duke made his debut in the major leagues on July 2, 2005. His rookie season was remarkable, as he posted an impressive 1.81 ERA over 14 starts, quickly establishing himself as a promising young pitcher.

Duke's early success with the Pirates earned him a spot in the starting rotation, and he continued to be a regular fixture on the mound for Pittsburgh over the next several seasons. In 2009, he was selected to the National League All-Star team, a testament to his performance that season. That year, he recorded a career-high 11 wins and pitched over 200 innings, showcasing his durability and skill as a starting pitcher.

After his tenure with the Pirates, Duke's career took him to several other teams. In 2010, he was traded to the Arizona Diamondbacks, where he spent a season before moving on to the Washington Nationals in 2012. During his time with the Nationals, Duke transitioned from a starting pitcher to a relief role, a change that would define the latter part of his career.

Duke's adaptability as a pitcher was evident as he embraced his new role in the bullpen. In 2013, he signed with the Cincinnati Reds, and later that year, he joined the Milwaukee Brewers. It was with the Brewers that Duke found a niche as a reliable left-handed specialist, posting a 2.45 ERA in 2014 over 74 appearances.

His performance with the Brewers led to a three-year contract with the Chicago White Sox in 2014. Duke continued to excel as a reliever, providing stability and experience to the White Sox bullpen. In 2016, he was traded to the St. Louis Cardinals, where he continued to be an effective option out of the bullpen.

Duke's career saw him don several uniforms, including those of the Minnesota Twins, Seattle Mariners, and Cincinnati Reds once again. His ability to adapt and perform in various roles made him a valuable asset to each team he joined. In 2019, Duke returned to the Cincinnati Reds, where he concluded his major league career.