Garrett will join the Marlins' Low-A affiliate at Greensboro this week and make his professional debut, Joe Frisaro of MLB.com reports.
Although the left-hander signed last season after being the seventh overall pick in the 2016 draft, the Marlins elected not to let him pitch due to his age and will hold his workload to about 100 innings this season. Garrett is just 19 but already has a plus curveball, solid changeup and a good feel for pitching, and if he adds some velocity to his fastball as he matures, he projects to be a true fantasy ace.