"In the second inning it just kind of really started to hurt a little bit and just got worse as the game went on," Peacock said. "I usually have this kind of pain on my bullpen day, and it just kind of came up on my start day."
Astros manager Bo Porter and assistant athletic trainer Rex Jones came out to the mound, where Porter made the decision to pull Peacock and go to the bullpen. Left-hander Kevin Chapman rushed out to warm up.
"[Peacock] was throwing the ball about as good as he's thrown all year, but whenever you start talking about forearm tightness, it's not something you want to take a chance with," Porter said. "We just felt like for precautionary measures, we were going to get him out of the game."
Peacock didn't feel the need to worry about any possibility of it becoming a bigger injury, though.
"I iced it already. It already feels a lot better," he said. "Just keep a close eye on it."
To that point in the game, Peacock gave up just two hits, striking out four without a walk. In his previous four starts, Peacock was 0-2 with a 10.50 ERA, walking 12 batters and striking out 14.
"[The discomfort] should happen more often though," Peacock joked. "It's the best I've thrown in a while."
Steve DiMatteo is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.