Luis Ayala, a right-handed relief pitcher from Mexico, made his Major League Baseball debut with the Montreal Expos. Known for his effective sinker and slider, Ayala quickly established himself as a reliable option out of the bullpen. His rookie season in 2003 saw him appear in 65 games, posting a commendable 2.92 ERA, which helped solidify his role as a dependable reliever.

Following the Expos' relocation, Ayala continued his career with the Washington Nationals. During his tenure with the Nationals, he maintained consistent performance, often being called upon in high-leverage situations. In 2005, Ayala pitched in 68 games, achieving a 2.66 ERA, which was instrumental in the Nationals' competitive season.

Unfortunately, Ayala's career faced a setback in 2006 when he underwent Tommy John surgery, causing him to miss the entire season. Despite this challenge, he returned to the mound in 2007, demonstrating resilience and determination. His comeback season saw him pitch in 44 games, though his performance was not at the same level as before his surgery.

In 2008, Ayala was traded to the New York Mets, where he continued to serve as a bullpen asset. His stint with the Mets was brief, but he managed to contribute to the team's efforts during the latter part of the season. The following year, Ayala signed with the Minnesota Twins, though his time there was short-lived, leading to a mid-season release.

Ayala's career saw a resurgence when he joined the Florida Marlins in 2011, followed by a successful season with the New York Yankees in 2011. With the Yankees, he posted a 2.09 ERA over 52 appearances, showcasing his ability to adapt and perform at a high level even after several years in the league.

In 2012, Ayala signed with the Baltimore Orioles, where he continued to be a valuable bullpen piece. His experience and skill set contributed to the Orioles' strong bullpen performance that season. Ayala's final MLB season came in 2013 with the Atlanta Braves and a brief return to the Orioles.

Throughout his career, Ayala was known for his ability to induce ground balls and his effectiveness against right-handed hitters.