"I see a lot of improvement since last year," he explained, "strength wise, speed wise and just like mental focus, from what I saw."
It was also a chance for him to speak with the coaches again.
"I talked to Coach Frey and all the coaches. Just about the game, what's going to happen and what I think about the game and stuff."
Zettel has offers from all across the country, some as an offensive lineman and some as a defensive lineman.
As for the Wolverines, he said, "They're recruiting me at both."
His visit schedule will continue over the next two weeks, as he visits two more Big Ten schools who are high on his list.
"Next week I'm going on my official visit to Iowa, and the next weekend, I'm going to the Notre Dame-Michigan State game."
Zettel also hopes to be fully recovered from injury by then and helping his team get back on track.
"We're 1-1 right now. We just lost to Petoskey. I've been playing, but I have a mid-foot sprain. I should be fully healthy soon."