Zellner (6-3, 220, 4.5) had visited Clemson and Maryland previously and will wrap up his trips at Miami (Fla.) Jan. 23.
"The visit went great," Zellner said. "I had a fun time. My host was the incoming freshman, Marcus Freeman. We hung out with some of the wide receivers as well as David Patterson.
"You could just feel that it is big time. That in the tradition. You could see that everywhere you look. It impressed me a lot."
Zellner said he is listing OSU and Clemson as his co-favorites going into the Miami visit.
"I know I will have a lot of thinking to do," he said. "I'm excited about going to Miami and it's my last visit. I hope to know where I'll be going sometime in the week after that visit."
Zellner had 17 sacks as a senior for a 13-1 team that reached the Class 3A state semifinals before falling to Miami Pace. He also excelled as a tight end.
Zellner holds a 3.1 GPA and has a qualifying test score.