Oliver Perez is a Mexican professional baseball player who has had a long and successful career in Major League Baseball (MLB). He is a left-handed pitcher who has played for several teams throughout his career, including the Pittsburgh Pirates, New York Mets, Seattle Mariners, Arizona Diamondbacks, Houston Astros, and Cleveland Indians.

Perez began his professional career in 1999 when he signed with the San Diego Padres as an amateur free agent. He made his MLB debut with the Padres in 2002, but it wasn't until he was traded to the Pittsburgh Pirates in 2003 that he really began to make a name for himself.

During his time with the Pirates, Perez established himself as one of the best left-handed pitchers in the league. He had a career-high 239 strikeouts in 2004 and was named to the National League All-Star team in 2005. However, his success was short-lived, and he struggled with injuries and inconsistency in the following years.

In 2006, Perez was traded to the New York Mets, where he continued to struggle with consistency. He was moved to the bullpen in 2008 but eventually returned to the starting rotation in 2009. That year, he had a career-high 15 wins and helped lead the Mets to the playoffs.

After his time with the Mets, Perez bounced around the league, playing for several teams over the next few years. He had some success with the Seattle Mariners in 2012, but it wasn't until he signed with the Arizona Diamondbacks in 2014 that he really began to turn his career around.

During his time with the Diamondbacks, Perez became a reliable reliever and helped the team make it to the playoffs in 2017. He continued to pitch well for the Houston Astros and Cleveland Indians in the following years, and as of 2021, he is still an active player in the league.

Overall, Perez has had a long and successful career in MLB, despite some ups and downs along the way. He has established himself as a reliable left-handed pitcher and has helped several teams make it to the playoffs over the years.