He also pitched in seven games in two years at ULL, but is not pursuing a future on the mound.
The 6-foot, 200-pound Harrison is the second outfielder the Giants took in the first seven rounds of the Draft. San Francisco selected Dylan Davis from Oregon State in the third round.
The Draft concludes Saturday, with exclusive coverage of Rounds 11-40 beginning on MLB.com at 10 a.m. PT.
Ryan Hood is an associate reporter for MLB.com. Follow him on Twitter @ryanhood19. This story was not subject to the approval of Major League Baseball or its clubs.