A 44th round selection by the Los Angeles Dodgers in the 2011 Major League Baseball Draft, Slater, the No. 1 rated prep player in the state of Florida according to Prospect Wire and an AFLAC All-American, did not sign, electing to attend Stanford. Slater appeared in just five games as a pinch hitter, and did not record a hit in three at-bats as a freshman at Stanford.

Slater was a two-time state champion, four-time All-Conference selection, Second Team All-State selection as a sophomore, Third Team All-State selection as a junior and team captain his senior year of high school.