"Certainly extra scary given where we are in camp", he said.
"We are confident he is going to be alright".
Harper was drilled with a 96 miles per hour fastball right in the ankle, which sent him to the ground in pain.
Harper stayed on the ground for a few moments, was checked by a trainer and limped off and out of the game in the sixth inning.
Harper, who signed a 13-year, $330 million deal with the Phillies on February 28, entered Friday's game with three walks and a pair of strikeouts in limited spring training action. The right-fielder was supposed to play in Spring Training games on Saturday and Sunday this weekend, but that seems unlikely now. He's now 0-for-5 with three walks in four Grapefruit League games.
"I think it's a little premature to speculate on lost at-bats or anything like that", Kapler said. "But again, not overly concerned right now".