Harper, who originally received a four-game ban for his role in a fight with Giants reliever Hunter Strickland, will start serving his three-game suspension as the Nationals face the Giants on Wednesday night, the source said.
Fox Sports was to first to report that Harper’s suspension had been reduced.
Strickland received a six-game ban for throwing a fastball at Harper during Monday’s game, which led to a bench-clearing brawl between the teams. He also filed an appeal.
Strickland hit Harper in the hip with a pitch in the eighth inning and the Washington slugger charged the mound, firing his helmet wildly before trading punches to the head with Strickland during the Nationals’ 3-0 win.
MLB chief baseball officer Joe Torre’s explanation of the disciplinary decisions said Strickland intentionally hit “Harper with a pitch, inciting the bench-clearing incident and fighting” while Harper’s suspension came “for charging the mound, throwing his helmet and fighting.”
Each player also was fined an undisclosed amount.
According to ESPN Stats & Information, this will be Harper’s second suspension. His first was in May 2016, for confronting umpire Brian Knight.
Information from The Associated Press was used in this report.