Chicago White Sox pitcher Jake Peavy was removed in the third inning of Tuesday's game against the Seattle Mariners with pain on the left side of his rib cage, and while X-rays were negative for a fracture, he'll undergo an MRI on Wednesday in Seattle, according to the team's website.
Peavy allowed six runs on seven hits over 2 1/3 innings in a second consecutive subpar outing. The 32-year-old yielded six earned runs over four innings against the Chicago Cubs on Thursday.
His fastball did not top 90 mph, according to the website.
"You can just tell by the way he was throwing that something didn't look right, so we went out and checked and he wasn't able to get any velocity on it," Chicago manager Robin Ventura said. "It was one of those, you don't want him to go out there and continue and hurt something."
The Associated Press contributed to this report.