On Tuesday they did so, designating right-hander Micah Owings for assignment.
Grandal, who signed a four-year deal with the club, will report to the player-development complex in Goodyear, Ariz., for a few weeks. He is expected to eventually join the organization's Rookie League team in Billings, Mont. The switch-hitting backstop hit .401 with 15 home runs and 60 RBIs at the University of Miami this past season.
Owings, 27, has appeared in 22 games for the Reds this season out of the bullpen, going 3-2 with a 5.40 ERA. He has 35 strikeouts in 33 1/3 innings of work.
Bailey Stephens is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.