Phil Myers was already a player to watch entering rookie camp and training camp. The undrafted free agent defenseman, now a top prospect with the Flyers, got a long look in training camp a year ago. With a long line of prospects filling available spots -- last season it was Robert Hagg and Travis Sanheim -- Myers was sent to the minors for his first full professional season with the Phantoms.

Myers steadily improved over his first season in the AHL, drawing more attention over the offseason as the possibility that he was the next prospect to make the jump to the NHL grew.

On Monday, the Flyers open rookie camp and Myers is among the participants. But for him, rookie camp and the subsequent training camp to follow will take on a new meaning.

On Sunday morning, the Flyers announced that veteran defenseman Andrew MacDonald will be out for six weeks with a lower-body injury sustained in an offseason workout. The injury opens the door for a prospect to make the opening night roster. Myers stands above all as the prospect to watch in regards to that spot.

Myers was already among the most talked about prospects entering camp. Alongside the likes of Carter Hart and Morgan Frost, the two headliners at the other positions, Myers has become a standout in the Flyers system.

Myers is really the last top defensive prospect in the Flyers system that appears to be close to the NHL. Shayne Gostisbehere started the migration of top prospects to the NHL in 2015. Ivan Provorov made the jump in 2016. Last season, Hagg and Sanheim got the call. With the exception of Sam Morin, whose road to the NHL has been marred by injury, Myers is the last of the group to make the jump.

With MacDonald still in the picture, it was difficult to see Myers making the Flyers without an incredible camp performance. Provorov is far and away the Flyers top defenseman. Gostisbehere and Hagg have locked in spots. Sanheim, who locked in a spot of his own in the latter part of the season, is expected to not only make the team, but take on a more significant role. MacDonald, Radko Gudas and the newly-signed Christian Folin serve as veterans on the blue line.

Myers was certainly a standout at development camp in June, a man among boys in the prospect group. There’s no doubt he’s among the strongest on the blue line next to a host of recently-drafted kids.

That said, Myers did have growing pains in the AHL, as to be expected, and struggled with injury there, something that has gotten in the way of his development. His health is of the utmost importance in his quest to lock up a roster spot for October.

For Myers, rookie camp begins a month-long tryout to prove he can fill MacDonald’s shoes and be a viable replacement. MacDonald’s six-week recovery could hold him out of action for eight regular-season games, which would also give Myers some time to make the decision a difficult one for the Flyers if they like how he’s performed to that point in the season.

While injuries are not a welcome sight before players hit the ice in training camp, this does create some intrigue and a bit of a roster battle. Those were fairly limited this season, unlike in season’s past, with only the bottom-six forward roles really being undetermined at this point.

It certainly seemed like the 2018-19 season was going to present an opportunity for Myers, opening the door for his NHL debut. That opportunity has come much earlier than expected, but it is one that could jumpstart a big camp for Myers.

Kevin Durso is Flyers insider for 97.3 ESPN and Flyers editor for SportsTalkPhilly.com. Follow him on Twitter @Kevin_Durso.