About 60 NFL coaches, including the New York Jets' coach and assistant Bill Callahan, joined forces for Mangini's 10th annual one-day Football Fundamentals Minicamp.
Saturday's event drew about 800 high school football players from the Northeastern part of the U.S., who took part in drills and 7-on-7 games in a light-hearted environment.
"It's the first coaching any of them have done since the end of last season. And I'd say they were a little rusty, early," Mangini jokingly told the Hartford Courant. "But they picked it up."
Ryan played the role of quarterback in a throwing drill and launched "a lot of deep passes," the Courant reported.
"I threw like 1,000 passes, and my shoulder, I mean, it's gone," Ryan said. "I was done after the first 100 throws, but I threw about 1,000."
Mangini arrived at this year's event without a job, having been fired by the Browns after back-to-back 5-11 seasons. He spoke to participants about moving forward, both on and off the field.
"In this business, you're going to get fired. That's just a fact, Ryan said. "Sooner or later, I'll be in the same situation, but it's nothing about him. He's a tremendous coach and a tremendous person. This event that he has every year just speaks to that. He's out of football, yet all these coaches come back.
"You just want to help him out as best you can. I'm sure it won't be long and he'll be back on the sidelines."