Mastromatteo, a 6-foot-1, 215-pound linebacker from Absecon (N.J.) Holy Spirit, verbally committed to UNC in May following an unofficial visit to the campus. However, he de-committed when Butch Davis was dismissed and then re-committed a few days later.
"It was really a rollercoaster ride," Mastromatteo said. "But everything worked out for the best for me. I'm so happy that it did. It was a waiting game most of the time, but it turns out I really love these coaches and they like me a lot so it really worked out great."
In particular, Mastromatteo quickly developed a bond with Dave Duggan, UNC's linebackers coach.
"I really like him as a coach and as a person," Mastromatteo said. "He's been to my house twice and he's been calling me as much as he can. We've really formed a really good relationship. That really helped me with everything that happened. Coach [Larry] Fedora has been to my house and he really finalized it all, but Coach Duggan is a great guy and a guy I look forward to playing for."
It hasn't exactly been determined where Mastromatteo will play for Duggan.
"[Duggan] said what's best about me is I could play almost all three of their [linebacker] positions," Mastromatteo said. "He sees me mostly as a ‘Mike' [middle linebacker], but I could play ‘bandit' or even ‘Will' [weak-side].
"I think it's great that I can play all the positions, because the more positions I could play, the earlier I could see the field."
Mastromatteo says he projects as a qualifier, according to the NCAA Clearinghouse.