Much was at stake Friday night at Safeco Field though the A's and Mariners' spots in the standings were decided some time ago.

Oakland which claimed the AL West title five days earlier was playing for home-field advantage in the Division Series and got it with an 8-2 victory powered by a three-run homer by Brandon Moss and a two-run pinch-hit shot by Derek Norris. That means that Game 1 of the American League Division Series will be on Friday at the Coliseum. The A's at 95-65 still could catch Boston for the best record in the league and Oakland holds the tiebreaker with the Red Sox.

The lone note of concern for Oakland on Friday: left fielder Yoenis Cespedes left with more right shoulder soreness after three innings.

Seattle was playing for lame-duck manager Eric Wedge who resigned earlier in the day.

Then there was A's starter Bartolo Colon who was pitching for the American League ERA title. He entered tied with Detroit's Anibal Sanchez who pitches Saturday at Miami and he allowed solo homers by Franklin Gutierrez in the first (ending Colon's streak of 19 scoreless innings) and Kendrys Morales in the sixth.

Colon's ERA stands at 2.65 after his final start of the season. Sanchez is at 2.64. The last time the A's had an ERA leader was 1994 when Steve Ontiveros also finished at 2.65.

Manager Bob Melvin said the team probably won't announce a Game 1 starter until Tuesday. However Colon is expected to get the nod.

Moss' homer was his 29th of the season and he has two games left to try to get to 30; his blast to right gave the A's their first runs off Hernandez this season. Norris' was his third pinch-hit homer of the year.