Ohio State sophomore big man Kaleb Wesson also entered the draft but is generally expected to be back in Scarlet and Gray next season.
He did not receive an invitation to the NBA Combine, either, though former Ohio State verbal commitment Darius Bazley did.
A forward from Cincinnati Princeton, Bazley de-committed from Ohio State after Thad Matta and the school parted ways in the summer of 2017.
Princeton guard talks about first game with the Vikings and looking forward to playing at Ohio State.
He later pledged to go to Syracuse before opting to skip college altogether.
He could have played in the NBA’s developmental G League last year but chose not to do that, either.
This year, for the first time, underclassmen can hire an agent and still return to school if they they terminate the agreement with the agent. The deadline for withdrawing from the draft is 5 p.m. June 10. The draft takes place June 20.
The combine is May 14-19 in Chicago.
Toppin averaged 14.4 points and 5.6 rebounds in his first season on the court with Dayton as a redshirt freshman. He arrived at UD in June 2017 but sat out the 2017-18 season as an academic redshirt. In the 2018-19 season, he was named to the All-Atlantic 10 first team. He was the first rookie to earn that honor in 20 years.
>>RELATED: How valuable is the Flyers program?
Wesson, a 6-foot-9, 270-pounder, led Ohio State in scoring (14.6 points per game) and rebounding (6.9) as a sophomore last season when the Buckeyes went 20-15 and advanced to the second round of the NCAA Tournament.
A year ago, Dayton's Kostas Antetokounmpo entered the draft with three years of eligibility remaining and was invited to the combine. He was eventually taken by the Dallas Mavericks in the second round.