Sidney Crosby was playing the best hockey of his life. Now his extraordinary year is on hold and no one is sure when he will be back on the ice.

Pittsburgh said Monday that its superstar center has been diagnosed with at least his third concussion just a few days before the defending Stanley Cup champion Penguins open their season.

Crosby finished as a Hart Trophy finalist as league MVP, won the Conn Smythe Trophy as playoff MVP and led Team Canada to the World Cup title just a few months after winning his second Cup with the Penguins.

His short- and long-term future is in doubt after another concussion, an injury that has dogged him off and on over six years.

Coach Mike Sullivan said Crosby was concussed in practice Friday and that there was no timetable for his return. The diagnosis came as the Penguins prepare to raise their championship banner Thursday night before a home game against the Washington Capitals.

Sullivan declined to reveal how the concussion happened. General Manager Jim Rutherford said Crosby was held out of the preseason finale against Columbus on Saturday because he wasn’t feeling well and didn’t practice Monday to go through concussion testing.

The 29-year-old Crosby took blows to the head during the 2011 Winter Classic and in his next game that year, on Jan. 5 against the Tampa Bay Lightning. He was out until November. A hit Dec. 5 knocked him out until March, with the combined absences limiting Crosby to just 69 games over over two seasons from 2010-2012.

JETS: Goaltender Ondrej Pavelec was put on waivers with Winnipeg intent on demoting him to the American Hockey League.

Pavelec has one year remaining on his contract that pays him $4.75 million. The 29-year-old with 371 games of NHL experience was passed on Winnipeg’s depth chart by younger goalies Connor Hellebuyck and Michael Hutchinson.

ISLANDERS: Winger Pierre-Alexandre Parenteau was waived just three months after signing a one-year $1.25 million contract after a year in Toronto.

The Islanders had brought back Parenteau, who played with them from 2010-2012, in the hopes he could rekindle some magic with John Tavares. Parenteau has 101 goals in 424 games.

AVALANCHE: Forwards Gabriel Bourque and Rene Bourque signed one-year contracts after they were invited to camp on a professional tryout.

The Bourques, who are not related, add depth to a forward crew that already includes Nathan MacKinnon, Gabriel Landeskog and Matt Duchene.

FLAMES: Winger Johnny Gaudreau signed a six-year deal after two impressive seasons in Calgary.

A former Boston College standout, he has been a restricted free agent.

FLYERS: Defenseman Radko Gudas was suspended by the NHL for six games for a late hit against Boston’s Austin Czarnik in a preseason game Saturday.