Sanchez stole second and Melky Cabrera walked to give the White Sox their first scoring chance. But Karns then struck out Jose Abreu to end the inning.
Karns became the first pitcher in the Majors this season to record a four-strikeout inning. He was the first Royals hurler to fan four in a frame since Kevin Appier on Sept. 3, 1996, against Toronto.
Rockies starter Jon Gray was the last Major Leaguer to achieve the feat (Sept. 17, 2016).
Jeffrey Flanagan has covered the Royals since 1991, and for MLB.