A 6-foot, 200-pound right-hander from Cal Poly, Slater was 1-1, 6.27 in 10 games as a sophomore at Cal Poly in 2015, with 10 strikeouts in 18.2 innings.
He was ticketed to join the Knights for the 2014 after his freshman year, but instead he was shut down for the summer because of a minor knee issue. He was 3-2, 6.20 in 14 games for the Mustangs in 2014, with 11 starts and 34 strikeouts in 49.1 innings.
Slater was 11-2, 1.34 in 2013 as a Carlsbad HS senior, with 90 strikeouts in 78.1 innings, seven complete games and five shutouts. He was the Avocado West League Pitcher of the Year, a first-team Avocado League all-star, and a first-team All-CIF-San Diego Section all-star.