As
@MaximumSam pointed out, the Buckeyes add a much needed transfer PG. CJ Walker had to sit out this year because he was a traditional transfer, not one of the newer graduate transfers.
Walker previously played two seasons at Florida State so he will be a Junior in the 2019-2020 season. As a sophomore at FSU in 2017-2018 he started and averaged 23.2 MPG, 8.0 PPG, and 2.4 APG. His addition should help a lot.
In addition, Ohio State has the B1G's #1 ranked (#12 nationally) recruiting class with three four-star freshmen coming in. The incoming freshmen are:
DJ Carton: A 6-1, 190# PG from Iowa. He is the #28 ranked recruit nationally, #4 at PG.
Alonzo Gaffney: A 6-9, 190# F from New Hampshire. He is the #42 ranked recruit nationally, #10 at SF.
EJ Liddell: A 6-6, 220# F from Illinois. He is the #45 ranked recruit nationally, #9 at PF.
In addition to the two Seniors who contributed significant minutes that I listed above, the Buckeyes also lose little-used Senior Joey Lane. Lane is a G who played in just nine games this past season.