Initial X-rays were negative, the club said. Harper then left the ballpark for more detailed X-rays.
"Bryce has a right foot contusion," Kapler said after a 3-2 win over Toronto. "Right now we don't have reason for major concern, but obviously we want to go inside and take a look first."
"Certainly extra scary given where we are in camp," he said. "We're confident and we understand we have a good club on the field and we're confident that Bryce is going to be all right."
Many in the crowd at Spectrum Field gasped when Harper was struck by a 96 mph fastball from Toronto rookie Trent Thornton in the sixth inning. The slugging outfielder went down to the dirt, clutched his ankle and stayed on the ground for a few moments.
Harper was checked by a trainer, limped toward the dugout with assistance and soon hobbled toward the clubhouse.
Recently signed to a record $330 million, 13-year contract, Harper was playing his fourth exhibition. He is 0 for 5 in 10 plate appearances.
Harper had hoped to play three straight games starting Friday.
"I think it's a little premature to speculate on lost at-bats or anything like that," Kapler said. "First and foremost, we probably have to get inside and meet with our medical team and discuss it. But again, not overly concerned right now."
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