Lowrie, who was standing with the aid of crutches in the clubhouse following a 3-2, 12-inning loss to the Giants, said he had undergone X-rays, but the results were not announced.
"My knee and ankle both hurt," Lowrie said. "I can't really tell you which is worse."
Lowrie had his right foot on the bag receiving a throw from second baseman Jose Altuve when Gregor Blanco slid into the base in the third inning. Blanco's foot went into Lowrie's ankle, pinning his foot down.
"He slid onto my foot, and while I was trying to get away from the base my foot was still underneath his foot, so my whole lower leg twisted," Lowrie said.
Lowrie needed assistance as he limped off the field. He was replaced by Brian Bixler.
"I think it'll get better," Lowrie said. "I'm hoping it's not a serious thing, but I still think we need to make sure it's not. There's no reason to guess. Let's just hope it's not something serious."
Lowrie came into the game hitting .254 with 14 homers, second most among National League shortstops. His .346 on-base percentage led NL shortstops.