After 18 years in the NFL, No. 18 is finally going to call it quits.

ESPN's Chris Mortensen reported Sunday that quarterback Peyton Manning will hold a press conference to officially declare his retirement Monday—exactly one month after the quarterback earned his second Super Bowl title and led the Denver Broncos to a 24-10 victory against the Carolina Panthers in Super Bowl 50.

The news has brought with it scores of praise from athletes across all sports, including a Facebook post from New England Patriots quarterback Tom Brady, a longtime rival of Manning.

For Duke head coach David Cutcliffe—who coached Manning during his college days at Tennessee from 1995-98—there was nothing but the highest of compliments to award his former signal-caller.

“I’m not a little biased, I’m a lot biased…. In my opinion, there’s no question, he’s the greatest quarterback to ever play the game,” Cutcliffe said. “I just think he’s the most impactful player who’s ever played the game at that position, and maybe period. Everyone will always have fun arguing that, but I’d stay up probably half the night arguing with them, if they wanted to.”

Although Manning went on to capture two Super Bowls and break several NFL records since leaving Knoxville, Cutcliffe has maintained a strong relationship with him and his family. Manning and his younger brother, Eli—whom Cutcliffe also coached in his younger days and has two Super Bowl wins of his own with the New York Giants—have come to Durham on a regular basis for offseason workouts with many of the receivers on their current teams.

After Peyton underwent neck surgery that forced him to sit out the 2011 season, he spent months rehabbing in Durham under Cutcliffe’s guidance. Cutcliffe pointed to those months the two spent together as some of his fondest memories of Manning, despite the rigorous struggles he went through to eventually return to the gridiron.

“At the beginning of it, there was nothing beyond trying to be better next week. It was literally at that point. There were a lot of conversations because I watched how hard he had to work, there were a lot of conversations at the end of the days that were based on, ‘Should I even be doing this? Am I wrong for trying to do this?’” Cutcliffe said. “That will never happen again like that where we shared something, and then watching this big great athlete, great player, a guy that had accomplished most anything anybody would want, work as hard as he did to get back. That’s something just everyone should have the opportunity to see, and I got the opportunity to watch that. That’s a pretty special moment.”

As for the next stage in Manning’s life, many have speculated he would naturally slide into an executive role within the NFL due to his intricate knowledge of the game and tireless work ethic. Cutcliffe said he did not think a coaching role would suit Manning, but agreed he could see him assuming a role within a professional organization if not pursuing a business career in other areas.

More than anything, though, Cutcliffe emphasized the range of opportunities Manning—who will turn 40 in three weeks—now has ahead of him without the day-to-day burden of playing quarterback in the NFL.

“My comment to him—and he’ll do whatever he wants to do, he’s really good at that—is take a year off and figure out how to not be an NFL quarterback. That will take a little while, right? That’s defined him for a long time,” Cutcliffe said. “I texted him, ‘Just enjoy some days.’ Whatever he says tomorrow, and then when he walks out of there—how awesome is that? It’s just you and your family and enjoy it. That’s all I want to see him do.”