"He's throwing a little bit and not feeling much better," manager Bob Melvin said Thursday.
Now there's concern that the issue, once believed to simply be a bout of tendinitis, could lead to surgery.
Griffin will meet with Houston-based Dr. Thomas Mehlhoff on Tuesday to decide if that's necessary. Mehlhoff performed Tommy John surgery on A's reliever Fernando Rodriguez on March 27, 2013, and Rodriguez is nearing the end of what's been a very successful rehab process.
Griffin, 26, was 14-10 with a 3.83 ERA in 32 starts in his first full season in the Majors last year, compiling a team-best 200 innings. But he was left off the American League Division Series roster because of elbow issues, which never went away. They only worsened with each start in Spring Training, and the A's opted to send him for tests with Dr. Doug Freedberg, who suggested Griffin undergo platelet-rich plasma therapy.
Griffin, penciled in as the club's No. 4 starter entering spring, did just that and was initially expected to return to the rotation in late May or early June -- an encouraging prognosis for a team that knew it would already be without righty Jarrod Parker, who succumbed to his second Tommy John surgery in late March.
Suddenly, Griffin could be facing the same fate, though the A's remain equipped with an enviable rotation that entered the day with an AL-best 2.80 ERA.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.