HOUSTON -- A's starter Drew Pomeranz will return to Oakland on Wednesday to have his left shoulder examined, at which point the club will determine whether the southpaw needs to go on the disabled list.
"Since he is going home, there's a chance he could go on the DL," said A's manager Bob Melvin. "It's something that's been going on for a little while, and we don't want it to continue to go on. But we haven't made a definitive decision."
Pomeranz exited his Monday start in Houston after 4 1/3 innings because of shoulder soreness -- specifically, AC joint discomfort.
No matter Pomeranz's prognosis, it appears likely that he won't be able to make his next scheduled start, on Saturday against the host Tampa Bay Rays. The A's have several fill-in options at Triple-A Nashville, including Kendall Graveman, who has allowed just five earned runs in 24 1/3 innings for a 1.85 ERA in four starts for the Sounds since being optioned.
Graveman last threw Sunday, tossing seven shutout innings, so he could pitch on five days' rest for the A's on Saturday, if asked.
• Ben Zobrist played five innings at second base and went 1-for-3 with an RBI single for Class A Advanced Stockton in his first rehab game from left knee surgery Tuesday.
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.