Right-handed reliever Joe Kelly exited the White Sox game against the Red Sox during the eighth inning Wednesday with a tight left hamstring.
Protecting a 3-1 lead, Kelly struck out Trevor Story looking and Franchy Cordero swinging to open the inning but winced after the strikeout pitch to Story.
He walked off with assistant trainer Josh Fallin. The Sox said Kelly will be re-evaluated Thursday.
“They are going to examine it and get a feel,” manager Tony La Russa said.
“But nobody said it would be easy. We’ve gone through this before. We’ll wait and see how [the] hamstring is.”
Liam Hendriks finished the inning by getting Christian Vazquez to ground out to shortstop Tim Anderson. Hendriks walked two in the ninth, but recorded his 14th save.
Kelly was pitching in his seventh game after starting the season on the injured list with a right biceps nerve injury. He had allowed six runs over five innings.