Harper's double with two outs in the bottom of the ninth scored two runs. He went 3-for-5 with two doubles, 2 RBIs and a strikeout in his second rehab start.
On Tuesday, Harper, who is recovering from a broken left thumb, went 2-for-3 with two home runs and four RBIs in Lehigh's 10-5 win over Gwinnett.
The original plan was for Harper to remain in Triple-A until Saturday, but it's possible that the timetable could be moved up, Phillies interim manager Rob Thomson said.
"I haven't talked to him yet," Thomson said of Harper on Wednesday. "I heard that he had another big night, so we'll need to talk to him and see where he's at."
Harper last played for the Phillies on June 25.
The Associated Press contributed to this report.