This is not how the Flyers wanted to start their training camp.

Mega-prospect Morgan Frost has a groin injury and will not play in Monday’s exhibition opener against the New York Islanders at the Wells Fargo Center.

Frost was going to center Isaac Ratcliffe and Joel Farabee. Cal O’Reilly, who had 16 goals and 67 points for Iowa and was an AHL all-star last season, will take Frost’s spot. O’Reilly, who will turn 33 later this month, is a five-time AHL all-star.

Frost, 20, trying to earn a spot on the Flyers’ roster, is listed as day to day. Coach Alain Vigneault downplayed the injury, saying that Frost tweaked his groin at practice Sunday and that he was held out for precautionary reasons.

Vigneault said there was a chance Frost could skate Tuesday.

The Flyers are also missing right winger Travis Konecny, a restricted free agent who is unsigned, and injured center Nolan Patrick.

All three young players could be key pieces in 2019-20.

Farabee, 19, said O’Reilly, a 13-year pro, was a “real good player, and the systems are in place, so we know what we have to do. I think we’ll have a lot of adrenaline playing our first game here."

It will be Farabee’s first time playing at the Wells Fargo Center.

“I’m pretty excited,” he said. “I’m sure I’ll be nervous up to game time, but after my first shift, I’ll be good to go.”

O’Reilly, who has spent time in the NHL with Nashville, Phoenix, Pittsburgh, Buffalo, and Minnesota, is looking forward to centering Ratcliffe and Farabee.

“I’ve seen them play here the last few days; they’re both really good young kids," he said. “They’re smart. It’ll be fine.”