7. The Red Sox Let Roger Clemens Walk
After 13 seasons together, the Boston Red Sox let Roger Clemens go in December 1996. He joined the division rival Toronto Blue Jays, winning the Cy Young award in the next two years. He then continued to torment his former team as a member of their biggest rivals, the New York Yankees, for five seasons. He won 162 games with a 3.21 ERA in 11 seasons following his tenure with Boston.