A day after clinching their second straight playoff spot, the A's locked up home-field advantage in the AL Wild Card Game by beating the Mariners 1-0 on Saturday night.
Oakland will host the Tampa Bay Rays on Wednesday at 5:09 p.m. PT.
The A's won four of seven regular-season meetings against the Rays this year. The two teams split a four-game series at the Coliseum in June.
Oakland went 52-27 at the Coliseum this season, good for the fourth-best home record in all of baseball. Tampa Bay has the second-best road record at 48-32, with one game remaining at Toronto.
The Rays will start All-Star right-hander Charlie Morton in the Wild Card Game. Morton, 35, is 16-6 with a 3.05 ERA in 33 starts this season. In two outings against the A's, he allowed just one run in 13 1/3 innings.
The A's have not yet announced their starting pitcher. The decision is between right-hander Mike Fiers and lefty Sean Manaea.
The winner of the AL Wild Card Game will move on to face the Houston Astros in the ALDS.