North Carolina sent offensive line coach Sam Pittman and associate head coach John Blake.
"Coach Pittman, he's saying I'm top priority," said Mattes. "He wants me – one of the best lineman in the state – there."
The Tar Heels' coaching staff continues to build upon the momentum created back in March.
"Ever since that visit I made up there for the Carolina-Duke game, I've been impressed with Carolina and I've always liked it," said Mattes.
As late as a week or so ago, Mattes was claiming Clemson, North Carolina, NC State, and Virginia as his favorites. However, he has since opened things up a bit.
"I did have a top five or four, but now that everybody has come I've just got to be open," said Mattes. "Whoever's interested in me, I'm interested in them"
By the beginning of his senior year, Mattes hopes to narrow down his list of options to five schools.
With the recent additions of Illinois, Maryland, Miami, and Michigan State, Mattes' scholarship offer list is quickly approaching 20 schools.
Over the summer, Mattes plans to camp at Clemson, NC State, and Virginia. He's also considering camping at UNC as well as a couple other schools.
Last Saturday during Scout.com's Combine held in Charlotte, Mattes had one of the better days among offensive lineman. He ran the fastest times in both the 20-yard shuttle (4.61 seconds) and L-Cone (8.00 seconds). He also recorded 5.18-second 40-yard dash, 25.3-inch vertical jump, and 8-foot-2 broad jump.