Harper fell to the ground and appeared to be in pain before he went back to the dugout.
He slowly made his way to the clubhouse with team trainers:
Manager Gabe Kapler told reporters Harper was diagnosed with a right foot contusion and would undergo X-rays.
"We don't have reason for major concern," Kapler said.
The biggest free-agent signing of the offseason, Harper entered Friday's game with three walks and a pair of strikeouts in limited spring training action.
Staying healthy will be crucial for Harper as he hopes to live up to his record-setting deal. He missed 51 games in 2017 and has missed at least 15 games in five of his previous seven seasons.
The Phillies will hold their breath and hope the new face of the franchise is not in serious danger of missing Opening Day after he joined the club midway through the spring.