COLUMBUS — Ohio State big man Zed Key gave four years of his college basketball career playing for the Buckeyes. He’ll have one final year of eligibility, and he’s choosing to spend that year elsewhere; he intends to enter the transfer portal after four seasons with the Buckeyes. The big man averaged 7.4 points and five rebounds per game across 121 career games at Ohio State. His best season came during his junior campaign, when he averaged 10.8 points per game. Key’s best game of the season this past year — and possibly his career — came in the upset win over then-No. 1 Purdue at home in mid-…