SEATTLE -- Bartolo Colon outpitched Felix Hernandez to reach 18 wins for the fifth time in his career, Brandon Moss hit a three-run homer in the first inning and the Oakland Athletics beat Seattle 6-2 Friday night in the start of Eric Wedge's final weekend as Mariners manager.
Wedge told his bosses he will not return for next season, saying it became obvious he did not have a future with the club.
"It's got to the point where it's painfully obvious to me that I just wasn't going to be able to move forward with this organization," he said before the game. "We see things differently and we talked about it, but it just got to the point where I couldn't continue to move forward. Ultimately, I didn't feel like I could continue to manage here with the circumstances the way they are."
Seattle, which has never reached the World Series is assured of its fourth straight losing season and dropped to 70-90.
Oakland (95-65) remained two games back of Boston (97-63) with two games left in the race for best record in the AL and home-field advantage throughout the post-season. The A's clinched home field in the AL division series starting next Friday.
Colon (18-6) became the first major leaguer in his 40s to win 18 games or more since Jamie Moyer was 21-7 for Seattle in 2003.
Colon allowed two runs and three hits for the AL West champions, including solo home runs by Franklin Gutierrez in the first and Kendrys Morales in the sixth. His 2.65 ERA is second in the AL behind the 2.64 of Detroit's Anibal Sanchez, scheduled to start Saturday at Miami.
Ryan Cook, Sean Doolittle and Grant Balfour completed the four-hitter.
Coco Crisp went 4 for 5 with a run scored, his third four-hit game this year.
Hernandez (12-10) finished the season with his fewest wins since going 9-11 in 2008. The 2010 AL Cy Young Award winner gave up three runs and five hits in six innings with six strikeouts and a walk, retiring 13 of his final 14 batters. He entered with 14 2-3 scoreless innings against the A's this season.
With 216 strikeouts in 204 1-3 innings, Hernandez joined Randy Johnson as the only Mariners pitchers with five seasons with 200 innings and 200 strikeouts. Hernandez topped 200 innings for the sixth straight season and is the first major leaguers since Johan Santana (2004-08) with five consecutive seasons with 200 innings and 200 Ks. strikeouts.
Oakland boosted its lead to 5-2 in the seventh when Oliver Perez walked Josh Reddick on four pitches and pinch-hitter Derek Norris homered. Josh Donaldson added an RBI groundout against Carter Capps. Norris hit an RBI double in the eighth off Tom Wilhelmsen and scored on Daric Barton's single.
NOTES: Oakland OF Yoenis Cespedes left in the fourth inning with shoulder stiffness. He was playing in the field for the first time since Sept. 13.