"I probably took 40-plus swings in the cage and then went to batting practice, hit three rounds just fine, went into the fourth round and it just started to grab on me a little bit," Phegley said. "I took about four swings, and it just continued to get a little worse every swing. I just thought, we'll just stop before it continues, and that was pretty much the last thing I did today and it's just continued to get worse doing absolutely nothing, so it's pretty frustrating."
Phegley was icing his left side during the game, in hopes of progress, but there wasn't any.
"It's pretty sore from whatever I did to it," he said. "I guess we'll just kind of keep an eye on it and see how it feels. I've never had any kind of issue like this before, so it's kind of mind-boggling to try to figure out right now."
Maxwell was 0-for-4, extending his hitless streak to 14 at-bats.
Jane Lee has covered the A's for MLB.com since 2010.