B. J. Ryan, a left-handed pitcher, made his Major League Baseball debut with the Cincinnati Reds. Drafted by the Reds in the 17th round of the 1998 MLB Draft, Ryan's journey in professional baseball began with modest expectations. However, his career trajectory took a turn when he was traded to the Baltimore Orioles in 1999 as part of a deal for Juan Guzmรกn. This trade marked the beginning of Ryan's development into a reliable relief pitcher.

During his tenure with the Orioles, Ryan gradually transitioned from a middle reliever to a setup man, and eventually, he became the team's closer. His performance improved significantly over the years, and by 2003, he had established himself as a dependable arm in the Orioles' bullpen. Ryan's ability to strike out batters was a key aspect of his pitching style, and he consistently posted high strikeout rates throughout his career.

The 2005 season was a breakout year for Ryan. He recorded 36 saves and was selected to his first All-Star Game, solidifying his reputation as one of the top closers in the league. His success with the Orioles caught the attention of other teams, and in the offseason, he signed a lucrative five-year contract with the Toronto Blue Jays, reportedly worth $47 million. At the time, this was the largest contract ever given to a relief pitcher.

Ryan's first season with the Blue Jays in 2006 was exceptional. He saved 38 games and maintained an impressive 1.37 ERA, earning him a second All-Star selection. His performance was instrumental in stabilizing the Blue Jays' bullpen, and he quickly became a fan favorite in Toronto. However, his career faced challenges in the following years.

In 2007, Ryan underwent Tommy John surgery after experiencing elbow pain early in the season. This surgery sidelined him for the remainder of the year, and he worked diligently to return to form. Ryan made a comeback in 2008, but his performance was inconsistent, and he struggled to regain the dominance he once had. Despite these challenges, he managed to save 32 games that season.

The 2009 season proved to be a difficult one for Ryan. His velocity decreased, and he struggled with control issues, leading to a decline in his effectiveness on the mound. In July of that year, the Blue Jays released him, marking the end of his tenure with the team. Ryan's time in the major leagues concluded shortly thereafter, as he did not sign with another team.

Throughout his career, B. J. Ryan was known for his intimidating presence on the mound, characterized by his tall stature and fiery demeanor.