Oakland is one game ahead of Tampa Bay for home field in the American League wild-card.
The American League playoff bracket is now set after the A's and Rays clinched their respective Wild Card berths on Friday night.
Oakland secured its spot before the team's first pitch against the Mariners on Friday. The Indians' 8-2 loss to the Nationals clinched the A's their second consecutive playoff berth. They lost to the Yankees at Yankee Stadium in the AL wild-card game last year.
The Rays will return to the postseason for the first time since 2013. They defeated the Blue Jays 6-2 on Friday to improve to 96–64. Tampa Bay will finish 2019 second in the AL East behind the Yankees.
Home field for the AL wild-card game has yet to be decided. The A's entered play Friday leading the Rays by a game.
The AL wild-card will be held on Wednesday, Oct. 2. First pitch is slated for 8:09 p.m. ET.