Saint John Sea Dogs defenceman Oliver Felixson, 18, has Hodgkin's lymphoma, a cancer of the blood and lymph nodes.
The team made the announcement on Thursday — two days shy of Felixson's 19th birthday.
Felixson, who is from Helsinki, Finland, did not attend the news conference, but did issue a written statement.
"As I'm sure you can imagine, this news came as a complete shock to me and to my family," he said.
"The past few days have been difficult, but they have been made easier by the presence of my parents, who flew over from Finland when we received my diagnosis."
'Treatable and potentially curable'
Hodgkin's lymphoma is "a treatable and potentially curable cancer," Dr. Elizabeth Zed, who is a member of the Horizon Health Network team working with Felixson, said in a statement.
Treatment consists of chemotherapy and/or radiation, depending on the individual patient factors, she said.
Felixson will be out of the lineup indefinitely while seeking treatment, officials said.
Mario Lemieux beat it
Pittsburgh Penguins' superstar Mario Lemieux was diagnosed with the same type of cancer in 1993 and continued his career after treatment.
Sea Dogs coach Danny Flynn said Felixson "did his research" about Lemieux having Hodgkin's lymphoma.
"He knows that the chance for recovery is good," said Flynn. "He's ready to beat this thing."
Sea Dogs president and general manager Trevor Georgie said Felixson's diagnosis has "affected everyone in the organization."
"Oliver is our friend and teammate, and a member of our family. We are all with him as he meets this challenge," he said.
The team's equipment manager, David (DK) Kelly, has also been battling cancer and has spoken with Felixson a number of times since his diagnosis.
"The main thing to tell him was that he's not alone," said Kelly. "There's going to be some long days, some tough days, but don't ever think you're alone because there's a whole army of people beside you.
"He's an 18-year-old kid that just found out he's got cancer, so I think he's doing great considering the news he just got," said Kelly. "You know I was fortunate I was twice the age when I found out."
The team will not be offering any further comments at this time and requests that Oliver's privacy, and that of his family, be respected while he is in treatment.
Felixson, who is six feet six inches tall and 230 pounds, was drafted in 2015 in the first round.
Of the team's 55 games to date, he has had two goals and seven assists.