Oliver Perez

San Diego Padres

Perez was signed by the San Diego Padres as an amateur free agent in 1999. He made his debut with the Padres in 2002. Perez did well for a rookie after being called up by the Padres in 2002, striking out over a batter per inning, but he suffered from control issues at times. He regressed somewhat in 2003.

Pittsburgh Pirates

In August 2003, Perez was sent by San Diego to Pittsburgh along with Jason Bay and Cory Stewart in the same trade that brought Brian Giles to the Padres.

Before the 2004 season, the team overhauled his pitching mechanics. His average of 10.97 strikeouts per nine innings was highest in the Majors (239 SO/196 IP); his 2.98 ERA was fifth in the National League (tied with Roger Clemens); and his 12–10 record could have been ever better with reasonable run support early in the season. Pirates' bats provided two or fewer runs in Perez' 16 starts before All-Star break, causing him to post a 5–4 record with five no decisions despite a 3.24 ERA. In that season, Perez pitched at least six innings and allowed three or fewer runs in 21 of his 30 starts (70%). Through this first three seasons, Perez had compiled a 20–25 record with 474 strikeouts and a 3.86 ERA in 412.2 innings. His 239 strikeouts that year are currently the third-most in a season by a modern-day Pirate, trailing only Bob Veale's 276 in 1965 and 250 in 1964.

By contrast, Perez's 2005 season was disappointing. He posted a 5.85 ERA in a season plagued by injuries. The Pirates were forced to place him on the disabled list on June 29 after he broke his toe kicking a cart following a loss to St. Louis. He missed two and a half months, returning in September to post a 4.58 ERA in 19.2 late season innings. Perez had also lost significant speed off his fastball.

Perez represented Mexico in the inaugural World Baseball Classic, where Mexico was eliminated in the second group stage.

In 2006, Perez opened the Pirates' season as the number one starter. On June 27, Perez was sent to the Pirates bullpen after struggling through the first half of the season with an ERA over 6.00. On June 29, he was sent to the Triple-A Indianapolis Indians, with Tom Gorzelanny being called up to replace him in the starting rotation.

New York Mets

On July 31, 2006, Perez and Roberto Hernandez were traded to the New York Mets in exchange for Xavier Nady. The Mets assigned Perez to their AAA affiliate, the Norfolk Tides. He was recalled to the Mets' major league roster on August 26, 2006. After two subpar starts, Perez threw a complete game shutout against the Atlanta Braves in the second game of a doubleheader on September 6, 2006.

After the Mets lost two starting pitchers to injury in the final week before the playoffs started, they were forced to use Perez in the playoff rotation. His first playoff start came in Game 4 of the NLCS, in which he picked up his first career postseason win. His second playoff start came in Game 7 of the 2006 NLCS vs the Cardinals, he went 6 strong innings allowing 1 ER, The Mets would eventually go on to lose the game 3–1.

Entering the 2007 season, there were concerns about the Mets' pitching staff and whether Perez could live up to his potential. However, Perez finished the 2007 season 15–10 with a 3.56 ERA, striking out 174 in 177 innings pitched, while walking only 79.

In the 2008 season, Perez was inconsistent, posting a record of 10–7 with a 4.22 ERA. He was also prone to big innings striking at any moment. An example would be in a start against the San Francisco Giants, he went ¹⁄₃ of an inning allowing 5 hits and 6 runs all of them earned. An example of his dominance would be his start against the New York Yankees on June 29, 2008. Perez went 7 innings allowing just one run on a home run by Wilson Betemit striking out a season high 8 batters. After the firing of manager Willie Randolph, Perez pitched better. At the request of Pedro Martinez and pitching coach Dan Warthen, he has changed his delivery to the plate. Instead of letting his head hang down when he makes his delivery, he now makes a bowing motion. He led the majors in walks, with 105.

On February 3, 2009, the Mets signed Perez to a three-year $36 million deal to return. On May 6, Perez was put on the disabled list due to patellar tendinitis in his right leg. He returned to the rotation on July 8, 2009.

On August 26, 2009, Perez was diagnosed with patellar tendinitis in his right knee and underwent undergo season-ending surgery. He finished the season 3–4 with a 6.82 ERA.

On May 15, 2010, manager Jerry Manuel moved Perez to the bullpen. Perez refused a minor league assignment to work on his pitching despite both his poor play and repeated attempts by the Mets' front office.

On June 5, 2010, the Mets placed Perez on the 15-day DL due to a patella tendinitis of right knee. As Perez was placed on the DL soon after refusing an assignment to the minor leagues a second time, the league investigated the timing of the DL stint, later clearing it. After July 21, Perez made only six appearances, all in relief. Perez finished the 2010 season with 0 wins, 5 losses, and a 6.80 ERA in just 46.1 innings pitched.

The Mets unconditionally released Perez on March 21, 2011, still being responsible for the remaining 12 million dollars on his contract.

Washington Nationals

On March 23, 2011, the Washington Nationals signed Perez to a minor league deal and assigned him to the Class AAA Syracuse Chiefs. Perez was later moved to the AA Harrisburg Senators.

Seattle Mariners

On January 19, 2012, the Seattle Mariners signed Perez to a minor league deal with an invitation to spring training. The contract contained a $750,000 bonus for making the Mariners 25-man roster and $250,000 in performance incentives. Perez was promoted from AAA Tacoma to the major league club on June 16 in the role of relief pitcher. In his first month back in the majors since 2010, observers took note of his improved fastball velocity and strikeout-to-walk ratio. In 2012, Perez went 1-3 with a 2.12 ERA with 29.2 innings in 33 games.

On November 3, Perez signed a one-year, $1.5 million deal with up to $600,000 in performance bonuses.

Arizona Diamondbacks

On March 10, 2014, the Arizona Diamondbacks officially announced that Perez had agreed to a two-year, $4.25 million contract,

Houston Astros

On August 7, 2015, the Arizona Diamondbacks traded Perez to the Houston Astros minor league pitcher Junior Garcia.

Second stint with the Nationals

On December 11, 2015, Perez signed a two-year, $7 million contract with the Washington Nationals.

Personal life

Perez and his wife have two children. They live in Paradise Valley, Arizona.