Matt Lindstrom left Chicago's 7-6 win over the Royals on Monday after he sustained an injury to what appeared to be his left ankle area in the ninth inning.
Lindstrom came on for the save opportunity and allowed a leadoff single to Nori Aoki. Alcides Escobar then laid down a sacrifice bunt back to Lindstrom. The closer charged for the ball, but it went between his legs as he came up limping after a few steps.
Lindstrom hobbled around the mound with teammates, the trainer and manger Robin Ventura surrounding him before being pulled in favor of Scott Downs.
"I don't even know what that was," Ventura said. "We're still checking on him, making sure he's all right. It didn't look good though."
Lindstrom has six saves and a 3.32 ERA in 18 appearances this season.
Jackson Alexander is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.