In a stunning turn of events on the eve of training camp, Steve Yzerman is stepping down as general manager of the Tampa Bay Lightning after building them into a perennial contender.

A person with knowledge of the move told The Associated Press on Tuesday that Yzerman is leaving his post and will be replaced immediately by longtime assistant Julien BriseBois. The person spoke to the AP on condition of anonymity because the team had not announced Yzerman's decision. The Lightning were expected to hold a news conference later Tuesday.

Yzerman's move comes days before the Lightning open training camp following a trip to the Eastern Conference final. Yzerman, 53, spent the past eight seasons as Tampa Bay's GM, a tenure that included five playoff appearances, two trips to the conference finals and an appearance in the 2015 Stanley Cup Final.

BriseBois, 41, had been an assistant to Yzerman since they joined the Lightning organization in 2010. For a number of years, he has been considered a future NHL general manager and takes over a team that should contend for years to come.

Tampa Bay is again one of the Cup favorites based on Yzerman's stellar record of drafting, developing and acquiring players. He promoted Jon Cooper to head coach in 2013, re-signed captain Steven Stamkos and locked up defenseman Victor Hedman to a long-term deal in 2016, traded for J.T. Miller and Ryan McDonagh at last year's trade deadline and got Nikita Kucherov signed to an extension this summer.

Yzerman, a Hall of Fame center with the Detroit Red Wings who won the Cup three times as a player, went into management immediately after retiring. He began his front office career as vice president of hockey operations under GM Ken Holland in Detroit and was part of a Cup winner in 2008 before getting the head job with the Lightning.

Holland signed a two-year contract extension at the end of last season to stay on as Red Wings GM.

Tampa Bay came two victories away from the second title in franchise history three years ago. Yzerman has also won Olympic gold medals in 2010 and 2014 as Canada's GM.