Harper, hit by a pitch in San Diego last month, said the pins will be there for four weeks, and although he wouldn't put a timeline on his recovery, he did say "I'll be back" this season.
Last week, Harper had successful surgery to repair his broken left thumb, interim manager Rob Thomson said, telling reporters on Wednesday that "it went very well."
Harper was injured by a fastball from San Diego Padres left-hander Blake Snell. A day later, the Phillies announced the National League MVP was to be sidelined indefinitely, officially placing him on the 10-day injured list.
Harper, 29, the reigning National League MVP, is hitting .318 with 15 home runs, 48 RBIs and a .985 OPS this season in 64 games despite a small tear in the UCL of his right elbow that has prevented him from playing the outfield since April 16. He has tried to avoid season-ending Tommy John surgery with a platelet-rich plasma injection and rest.
The Phillies (42-38) were eight games behind the first-place New York Mets in the National League East before Tuesday's game.
The Associated Press contributed to this report.