Clay Buchholz, a right-handed pitcher, began his Major League Baseball career with the Boston Red Sox. Drafted by the Red Sox in the first round of the 2005 MLB Draft, Buchholz quickly rose through the minor league ranks, showcasing his potential as a starting pitcher. His major league debut came on August 17, 2007, against the Los Angeles Angels, where he pitched six innings and allowed just three runs.

A highlight of Buchholz's career occurred early on, during his second major league start on September 1, 2007. Facing the Baltimore Orioles, he threw a no-hitter, becoming the first Red Sox rookie to achieve this feat. This performance set high expectations for his future in the league.

Throughout his tenure with the Red Sox, Buchholz experienced both highs and lows. In 2008, he struggled with consistency and spent part of the season in the minor leagues. However, he rebounded in 2009, finishing the season with a 7-4 record and a 4.21 ERA. His performance helped solidify his place in the Red Sox rotation.

The 2010 season saw Buchholz establish himself as one of the team's top pitchers. He posted a 17-7 record with a 2.33 ERA, earning him an All-Star selection and a sixth-place finish in the American League Cy Young Award voting. Injuries, however, began to affect his career, limiting his playing time in subsequent seasons.

In 2013, Buchholz played a crucial role in the Red Sox's World Series championship run. Despite missing a significant portion of the regular season due to injury, he returned in time for the playoffs. He contributed with solid performances, including a key start in Game 4 of the World Series against the St. Louis Cardinals.

Buchholz's time with the Red Sox came to an end after the 2016 season when he was traded to the Philadelphia Phillies. His stint with the Phillies was short-lived, as he suffered a season-ending injury after just two starts. In 2018, he signed with the Arizona Diamondbacks, where he experienced a resurgence, posting a 7-2 record with a 2.01 ERA in 16 starts.

The following year, Buchholz joined the Toronto Blue Jays. His performance was hampered by injuries once again, and he finished the season with a 2-5 record and a 6.56 ERA. After the 2019 season, Buchholz did not sign with another team, effectively bringing his major league career to a close.

Over the course of his career, Buchholz was known for his pitching repertoire, which included a fastball, curveball, changeup, and cutter.