Meche debuted with the Mariners on July 6,, two months shy of his twenty-first birthday, making him the second-youngest debut for the Mariners at that time. Pitching with a 2-1 lead over the Anaheim Angels and two outs in the sixth, Meche walked two consecutive batters to force in a run and surrender the lead. He ended up with a no-decision. His first win came on July 19 against the Arizona Diamondbacks. For the season, Meche went 8-4 with a 4.73 earned run average. Meche lost his first four decisions of the season. On June 13, 2000, he tossed a one-hitter against the Kansas City Royals. After coming back to go 4-0 with a 2.64 ERA through his July 4 start against Anaheim, Meche was lifted in the sixth inning having thrown 113 pitches. His season was cut short due to what was thought at the time to be a dead arm. He went 1-2 with a 3.15 ERA in five rehab starts, but did not pitch at the major league level again for the rest of the season. In February, Meche underwent arthroscopic surgery to partially repair a frayed rotator cuff, and at the time he was expected to only be on the disabled list for six months. As it turns out, he ended up missing the entire season, and undergoing surgery again on October 3, 2001 on his right AC joint. Meche went 4-6 with a 6.51 ERA in for the Texas League's San Antonio Missions, but did not pitch at the major league level again until April 5,. Despite giving up four first inning runs, and taking the loss against the Texas Rangers, Meche came back to pitch four solid innings in which he allowed just two earned runs on solo shots by Iván Rodríguez and Juan González. From there, Meche went 15-13 with a 4.59 ERA in what was at the time far and away a career high 186.1 innings pitched to earn the Sporting News' American League Comeback Player of the Year award. Meche's season got off to a slow start as his record stood at 1-5 with a 7.06 ERA following a June 1 start against the Toronto Blue Jays. He was optioned to the Pacific Coast League's Tacoma Rainiers, and returned to the M's on July 30, to go 6-2 with a 3.95 ERA in thirteen second half starts. In 2005, Meche won 10 games despite posting an ERA of 5.09 and failing to reach 150 innings despite pitching in 26 starts. He averaged less than 6 innings in over half of his starts. In 2006, Meche won 11 games while losing 8 in 32 starts. He struck out 156 batters in 186.2 innings.
Kansas City Royals
After signing one year contracts with the Mariners for the and seasons, Meche signed a five-year contract with the Kansas City Royals on December 7, 2006 worth $55 million, matching Mike Sweeney's contract as the largest in club history until Alex Gordon agreed to a four-year $72 million deal in 2016. His record stood at 5-6 with a 3.54 ERA when he was named the Royals' sole representative at the 2007 Major League Baseball All-Star Game in San Francisco. Meche finished the season with a 9-13 record, while posting career bests in ERA, innings pitched and a league-leading 34 starts. Meche led the American League with 34 starts again in, while improving to 14-11 with a 3.98 ERA, and pitching over 200 innings for the second consecutive year for a Royals club that finished 75-87 and in fourth place in the American League Central. On June 16,, Meche pitched a four-hit shutout against the Diamondbacks to improve his season record to 4-5 with a 3.31 ERA. The 132 pitches he threw, however, took a toll on Meche and he began experiencing back and shoulder problems soon afterwards. For the rest of the season, Meche went just 2-5 with an 8.06 ERA. For the first time in his Royals career, 31-year-old Meche did not receive the opening day nod for Kansas City in. Instead he was slated as the number-two starter behind reigning AL Cy Young Award winner Zack Greinke. Hampered by injuries again, Meche spent considerable time on the DL in 2010 and was 0-4 with a 6.66 ERA after making his final career start on May 25. After five rehab appearances with the Northwest Arkansas Naturals and Omaha Royals, Meche returned to the Royals as a reliever that September. He made eleven appearances, giving up three earned runs in thirteen innings.
Retirement
Despite a guaranteed contract that called for a $12 million salary in 2011, Meche chose to walk away from the game on January 18 as he considered it unfair for the Royals to pay him millions if he would be out all year in the last year of his contract.
In popular culture
The rock group Band of Horses, which was founded in Seattle in 2004, wrote and dedicated their song "Wicked Gil" to Meche.
