Samuel Morin's hard-luck season is over.

The hulking defenseman, one of the Flyers' top prospects, will have knee surgery and will not be available to the Lehigh Valley Phantoms as they continue their quest for the AHL's Calder Cup title.

The Phantoms will face Toronto in the Eastern Conference finals starting Saturday.

After missing about 3½ months because of a suspected groin injury, Morin returned to action and played in parts of three playoff games in the conference semifinals. He was injured in the first period of Game 4, a five-overtime epic that the Phantoms won, 2-1, against Charlotte.

"He'll have the surgery once the swelling goes down in his knee," Phantoms coach Scott Gordon said Wednesday.

The 6-foot-7, 227-pound Morin, a restricted free agent this summer, was favored to win a spot with the Flyers next season and give the team physicality and help its weak penalty kill. But his latest injury may slow down the timetable.

Morin, who turns 23 on July 12, was the Flyers' first pick (11th overall) in the 2013 draft.

Before his latest injury, Morin remained optimistic about his future. Being sidelined, he said earlier this month, "made me realize how much I want to play hockey, how much I miss it. At the end of the day, I'll be back stronger."

Gordon said he is hopeful that two of his injured players, defenseman Travis Sanheim and center Phil Varone, will return to the Phantoms' lineup for Saturday's series opener in Toronto. He also said goalie Anthony Stolarz has been cleared to play after being sidelined by a knee injury.

Center Morgan Frost, coming off a 112-point season in the Ontario Hockey League, will join the Phantoms for their series against Toronto. Unless there's an injury to another center, however, it would be surprising if he played.

Goalie Carter Hart, who dominated the Western Hockey League, will join the Phantoms when they return home before Game 3 of this series, Gordon said. Hart is even more unlikely to play than Frost but will benefit from the experience.