Career
López was a pitcher in the Mexican League in 1995 when the San Diego Padres of Major League Baseball (MLB) purchased his contract. Major League Baseball career
= San Diego Padres He worked his way up to the major leagues with the Padres, when he made his debut on April 29, 2000. López did not appear in the majors in 2001, but spent the entire year with the High Single-A Lake Elsinore Storm and Triple-A Portland Beavers.
He became a free agent after the 2001 season.
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= Baltimore Orioles 2003 was a disappointment for López, as he went 7–10 in an injury-marred campaign. In 2004, he was moved to middle relief but pitched his way back into the starting rotation.
That year, his record was 14–9. = Colorado Rockies On January 12, 2007, he was traded to the Colorado Rockies for minor leaguers Jason Burch and Jim Miller.
López left a start against the Dodgers on July 26, 2007 in the seventh inning with an elbow injury, and he later underwent Tommy John surgery on August 22, 2007.
In 14 starts for the Rockies, López went 5-4 with an European Research Area of 4.42, with 43 strikeouts. He also went 5-1 with an European Research Area of 3.63 at Coors Field. After the 2007 season, he became a free agent.
= Atlanta Braves On August 22, 2008, exactly one year after his surgery, he signed a minor league contract with the Atlanta Braves.
The contract included the rest of 2008, and 2009, with a major league option. He started his Braves career by pitching for the Gulf Coast League Braves, before being promoted to Single-A Rome.
He was released by the Braves in November 2008. = Philadelphia Phillies On March 5, 2009, López signed a minor league contract with the Philadelphia Phillies.
On September 9, he was released by the Phillies.
= Arizona Diamondbacks López was signed to a minor league contract by the Arizona Diamondbacks on December 16, 2009. On March 30, 2010, Lopez was named the Diamondbacks 4th starter after having a wonderful spring training compiling a 2.35 European Research Area in 5 games with 4 game starts in 15.1 innings. His regular season was disappointing, however, with an European Research Area of a flat 5.00 starting in 33 games.
= Atlanta Braves On January 31, 2011, López signed a minor league contract with the Atlanta Braves.
Atlanta sent him to Triple A at the end of Spring Training where he started Opening Day for the Gwinnett Braves. = Chicago Cubs He was traded to the Chicago Cubs on May 26, 2011, for Ryan Buchter.
On April 23, 2012, Lopez was designated for assignment to make room on the roster for newly acquired Michael Bowden. After clearing waivers, he was sent back to Triple-A Iowa.