Seattle enters 37-31 at home while Oakland brings a 54-86 record and Jack Perkins starts against Kade Anderson in the opener.
The Seattle Mariners hosted the Athletics on Thursday to begin a series, with pitchers Kade Anderson and Jack Perkins starting the opener as Seattle leads 4-2.
Seattle enters with a 66-74 record, including a 37-31 home mark, while the Athletics sit at 54-86 overall with a 29-42 road record.
Mariners infielder Cole Young has 16 home runs, while catcher Cal Raleigh is batting 11 for 35 over his last 10 games; Athletics infielder Jeff McNeil leads his team offensively.
Texas Rangers pitcher Nathan Eovaldi threw a 25-pitch bullpen session Thursday without restriction, following his placement on the 15-day injured list August 10 due to elbow inflammation.
Eovaldi's next step depends on his physical response Friday, with the team deciding between another bullpen session or live batting practice.