Marincov broke out in his 2012 season as the top hitter on a solid North Florida squad. He hit .332 in 55 starts for the team, driving in 40 RBIs and hitting nine home runs. He played an injury-shortened freshman season in 2011, making 32 appearances and 27 starts. Over the course of that year he batted .274 with five home runs and 25 RBIs, and batted .310 in conference play. In high school the Orlando, Florida native led his Timber Creek high school squad to three district semi-finals and a state semi-final. He was named All-State in 2009 and was selected as the 6A District 10 Player of the Year in 2010. The Detroit Tigers drafted him in the 2010 MLB amateur draft in the 48th round out of high school.