The Pirates announced Monday that Harrison has a fractured fifth metacarpal. The veteran leadoff hitter was placed on the disabled list before Pittsburgh's home game Monday against the Colorado Rockies. Infielder Max Moroff was recalled from Triple-A Indianapolis to take Harrison's spot on the roster.
Harrison was hit on the hand by a 96 mph pitch in the third inning of Sunday's game against the Miami Marlins. He admitted to feeling "a little bit of pain" in his hand after the game.
Harrison is batting .263 with one homer and five RBIs. He came into the game Sunday leading the team with 12 runs.
Harrison missed the final month of the 2017 season after being hit by a pitch on the same hand. He was hit 23 times last year to rank second in the majors.
Todd Tomczyk, the Pirates' director of sports medicine, called the injury recurrence "very uncommon.''
The Associated Press contributed to this report.