Unlike last season, when it was clear the Flyers were going to have at least a couple prospects graduate to the NHL, nearly the entire roster can be written in ink before training camp even begins.

Monday starts a three-day rookie camp before an exhibition against the New York Islanders rookies Wednesday on Long Island and it’s entirely possible that none of the Flyers’ prospects will start the season in the NHL.

That’s not to say it’s impossible. Injuries and trades are hard to predict, and the Flyers don’t have any pressing needs that they feel won’t be filled by last year’s players simply improving.

“You build your team, you put your pieces together,” general manager Ron Hextall told the Courier-Post recently. “We feel like we got another good piece there with (James van Riemsdyk), but in the end all of our players have to come in here in shape and ready to go and ready to take another step. Quite frankly, we expect to take another step forward. We’ve got a lot of young players on our team that can get better. Again, adding JvR and Christian Folin we feel like we’re a better team and now it’s time to stick our nose to the grindstone and take another step.”

Here are the top three candidates from rookie camp to surprise the Flyers and add to their group.

ROSTER:Who's coming to rookie camp

Oskar Lindblom, LW, 2014 fifth-round pick

OK, this is basically cheating because Oskar Lindblom making the roster is basically a layup.

He has, by far, the best chance of anyone on the rookie camp roster to make the trip to Las Vegas for the Flyers’ season opener. Because he played fewer than 25 games last season (23 to be exact), he’s still a rookie by the NHL’s standards so he’s still part of rookie camp.

The Swedish left wing was recalled in February when Wayne Simmonds went down with a torn ligament in his hand, and played quite well. It took him 14 games to get his first goal but he was oh-so-close several times before that and played the responsible defensive game that kept him around until the last round of cuts last fall.

This year’s training camp will probably present a surprise or two for the big picture, but Lindblom figures to be third on the depth chart at left wing behind Claude Giroux and James van Riemsdyk.

Morgan Frost, C, 2017 first-round pick

When the Flyers opted to let Valtteri Filppula walk in free agency it looked like there might be a window for Morgan Frost, who was terrific in the Ontario Hockey League last season. And there’s plenty of precedent for the Flyers to include a teenager on their roster. Last year Nolan Patrick made it at age 19 and same for Travis Konecny and Ivan Provorov in 2016.

Then general manager Ron Hextall kept pumping the tires of Jordan Weal, who was wholly underwhelming last season and was, at times, healthy scratched. Could that be a defense mechanism by Hextall to avoid pressure on Frost? Sure, but with the Flyers looking for more speed down the middle than Filppula was able to provide Weal is definitely a legitimate option and another player that Frost would have to beat to win a job.

“I think my opinion’s probably different than other people’s,” Frost said back in June at development camp. “I want to make the team. I think if I work my hardest it’s realistic.”

Last season with the Sault Ste. Marie Greyhounds Frost racked up a league-high 70 assists in 67 games and was three shy of the league lead in points with 112. He was also an unreal plus-70, which was 17 higher than anyone else in the league. No doubt he showed he could dominate at the OHL level, but the Flyers have enough depth at the highest level that he’ll have to have an unbelievable training camp to prove he’s ready for the NHL now.

Carter Hart, G, 2016 second-round pick

Chances are pretty slim that the Flyers’ franchise hopeful goalie starts in the NHL this year. Despite a stellar junior career, Carter Hart would likely have to blow the doors off in training camp and see at least one of the four other goalies under contract get hurt during camp for him to have a legitimate shot of starting his pro career with the Flyers as opposed to the Lehigh Valley Phantoms.

“You’re going from playing with boys to men,” Hart said back in June during development camp. “Obviously it’s going to be a jump up, but you just have to adjust and adapt to everything and you’re not gonna get the guys just coming in, the little 16-year-olds with a flip shot. Guys can shoot the puck a lot harder. I’ve experienced that with the Phantoms and with camps here. I think you just have to adapt and adjust.”

Hart spent a couple days with the Phantoms during last season’s playoff run after his Everett Silvertips had been eliminated from the WHL postseason and he did the same in the spring of 2017 but hasn’t played an AHL game yet.

In fact, he hasn’t even played an NHL preseason game. He was scheduled to play a game last season but got sick and when he went back to Everett he learned it was mononucleosis, claiming the first part of his season.

The Flyers have high hopes for Hart and he may make have an excellent training camp, but he’s only on this list because he has a slim chance and most others have none at all.

Honorable mention

Hextall has recited the line many times that he doesn’t want older players to “block out” one of their younger players. A look at what the Flyers have on paper shows few spots available, though.

Of those in rookie camp, center Mikhail Vorobyev and defenseman Phil Myers are close to being NHL ready in the eyes of the Flyers’ front office. If the team opts to trade a veteran or waive and demote a player like high-priced Jori Lehterä, who is in the last year of his contract, it’s probably because one of those players (or others not in rookie camp like Nicolas Aube-Kubel or Cole Bardreau) pushed the envelope and won a spot.

Dave Isaac; @davegisaac; 856-486-2479; disaac@gannett.com

PART I:Pre-training camp Q&A with Flyers GM Ron Hextall

PART II:Pre-training camp Q&A with Flyers GM Ron Hextall

#FlyersMailbag:Questions ahead of training camp