Manager Joe Maddon noticed Hammel clenching his right hand, so he and athletic trainer PJ Mainville went to the mound to check on him after he'd thrown two pitches, both balls, to Gordon Beckham leading off the Atlanta sixth. Hammel stayed in the game, threw two more balls to walk Beckham and was then pulled.
Was it dehydration?
"It's frustrating," said Hammel, who experienced something similar in his first start with the Athletics in 2014. "I felt good today. Save for one mistake, I felt really good. There were a lot of good things on the mound, a lot of good things with [catcher Willson Contreras]. He brings a great, great, great ton of energy behind the plate, and he's picking us up right now. His game calling has gotten better every time. It's disappointing to not be able to finish what I started."
That one mistake was a fastball to Nick Markakis in the first inning that resulted in a two-run homer.
Hammel began to feel the discomfort in the sixth.
"It's just annoying -- I felt great," he said. "It ticks me off."
Hammel had thrown 80 pitches at that point and given up three hits, including Markakis' homer, coming off a rough outing against the Mets in which he gave up a career-high five home runs over four-plus innings.
Kyle Hendricks, who was not scheduled to start until after the All-Star break, warmed up in the bullpen while Hammel was being checked, but it was Travis Wood who took over in the sixth before making way for Hendricks.
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.