Selected 51st overall as a supplement pick in the 2012 First-Year Player Draft, Valentin was hitting .282 with 22 doubles, nine triples, seven home runs, 47 RBIs and a .785 OPS in 107 games with Great Lakes.
He struggled in 33 games with Great Lakes last season, posting a .618 OPS, but has improved at the plate this year.
Valentin will report to Class A Clearwater.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.