PITTSBURGH (Reuters) - Sidney Crosby's return from concussion is uncertain following several recent consultations with medical specialists but the Pittsburgh Penguins captain found time this week to make one of his fans very happy.

Crosby, who has not played in the National Hockey League (NHL) since suffering a concussion in early January, spoke to an 11-year-old boy who is battling cancer, giving him various tips about the sport and words of encouragement.

"I am really lucky to have the opportunity to help others and I am glad I was able to talk to Matthew," Crosby said in a statement on Thursday about his telephone conversation with the Ontario boy who said the chat was a dream come true.

"Other young people should reach for their dreams and if I can encourage that I am certainly happy to."

Crosby's own immediate dream is to return to the NHL in time for Pittsburgh's first regular season game on October 6, though that may be unlikely according to the player's agent.

"We always knew this was going to be a progressive recovery -- based on how he felt," Crosby's agent Pat Brisson was quoted as saying on the Penguins website.

"With a concussion, there is not a finite recovery period ... That's why we've never even set a specific goal for a return date like the start of training camp or October 1 or anything else. He will play when he is symptom free."

"We've had him see leading specialists because we want to make sure he gets the best care possible," Brisson said. "The Penguins always encourage their players to get second and third medical opinions and have been very supportive of this."

Since joining the Penguins for the 2005-06 season Crosby has been a points-producing machine, recording 572 points in 412 regular season games, has won a Stanley Cup and been named the league's most valuable player.

(Writing by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue)