Harper suffered a bruised right foot. Kapler said the swelling reduced overnight.
Initial X-rays were negative, the team said Friday. Harper then left the ballpark for more detailed X-rays.
Harper went down to the dirt after being struck by a 96 mph fastball from Toronto rookie Trent Thornton.
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.
Recently signed to a record 13-year, $330 million contract, Harper was playing his fourth exhibition for Philadelphia. The slugging outfielder is 0-for-5 in 10 plate appearances.
Information from The Associated Press was used in this report.