The procedure was performed by Dr. Neal ElAttrache in Los Angeles.
The Phillies said Harper is expected to return as a hitter only by the All-Star break and could return to playing right field by the end of the regular season.
Phillies president Dave Dombrowski had told reporters last week that Harper would have the elbow surgery, although it wasn't known if it would be of the Tommy John variety.
"We have no prognosis, really, until [the surgeon] goes into the elbow and takes a look at it," Dombrowski said then.
Harper tore his UCL in April, and it prevented him from playing in the field the rest of the season. He received a platelet-rich plasma injection in his right elbow in May and shifted to the designated hitter role thereafter.