Drew Pomeranz is expected to undergo arthroscopic surgery on his left AC joint.
A's vice president Billy Beane said Monday that Josh Reddick is a candidate for a contract extension.
Athletics promoted Billy Beane to vice president of baseball operations and David Forst to general manager.
Mark Canha homered, but the Athletics lost the final game of the season 3-2 to the Mariners on Sunday.
Chris Bassitt got a no-decision after giving up two runs in six innings during Sunday's loss to the Mariners.
Billy Burns is not in the Athletics' lineup Sunday.
Stephen Vogt is not in the Athletics' lineup Sunday.
Marcus Semien hit a two-run homer in the top of the 13th to help the A's beat the Mariners 7-5 on Saturday.
Sean Nolin allowed three runs over five innings Saturday in a no-decision against the A's.
Doctors have recommended that Drew Pomeranz undergo a clavicle resection.
Aaron Brooks pitched seven innings of two-run ball Friday in defeating the Mariners.
Danny Valencia went 3-for-4 with his 17th homer and 23rd double Friday against the Mariners.
Athletics manager Bob Melvin said that he wouldn't hesitate to use Barry Zito out of the bullpen on Sunday if the right situation arises.
Sean Doolittle gave up a run in 1 2/3 innings, but got his third save as the Athletics edged the Angels 8-7 on Wednesday.
Barry Zito, likely making his final major league start, got a no-decision after yielding two runs in four innings as the Athletics beat the Angels on Wednesday.