Ryan Thompson's journey through Major League Baseball began when he was drafted by the Toronto Blue Jays in the 13th round of the 1987 amateur draft. His professional debut came in 1992 with the New York Mets, a team he joined as part of a trade deal that sent David Cone to the Blue Jays. Thompson's time with the Mets marked the start of his major league career, where he played as an outfielder.

During his tenure with the Mets, Thompson showcased his skills as a right-handed batter and outfielder. He played with the team until 1995, demonstrating his abilities both at the plate and in the field. His performance with the Mets was characterized by moments of brilliance, although consistency was sometimes elusive. Thompson's time in New York was marked by a blend of potential and challenges, as he worked to establish himself in the major leagues.

In 1996, Thompson moved to the Cleveland Indians, where he continued to play as an outfielder. His stint with the Indians was brief, and he soon found himself with the Houston Astros later that year. With the Astros, Thompson had the opportunity to further develop his game, although his time with the team was also short-lived.

The following year, Thompson joined the New York Yankees, adding another chapter to his career. Playing for the Yankees in 1997, he contributed to the team as a part-time player. His role with the Yankees was limited, but it provided him with the experience of being part of a storied franchise.

Thompson's career continued with the Florida Marlins in 1998, where he played for a season. His time with the Marlins was another step in his journey through the major leagues, as he sought to find a lasting place in the game. In 1999, Thompson joined the Milwaukee Brewers, where he played for two seasons. His tenure with the Brewers allowed him to spend more time on the field, contributing to the team as an outfielder.

In 2001, Thompson signed with the Cincinnati Reds, marking the final stop in his major league career. His time with the Reds was brief, and he played his last major league game in 2002. Over the course of his career, Thompson played in 416 games, recording a batting average of .243, with 52 home runs and 176 runs batted in.