It's a half hour after practice, and not all of the Buffalo Sabres are off the ice. When coach Dan Bylsma's formal session ends, forward Ryan O'Reilly takes over by working a handful of teammates through a series of drills.

"There's always a bunch of guys that want to do extra stuff," O'Reilly said. "We just feed off each other."

Actually, it's the Sabres players who are the ones benefiting most by feeding off O'Reilly, who has emerged as the team's on- and off-ice leader in his first season in Buffalo. Overshadowed for the most part during his first five seasons in Colorado, O'Reilly has needed just seven months in Buffalo to show he's capable of being a top-caliber player.

"Guys look to him for a lot of things," defenseman Zach Bogosian said. "His demeanor and his leadership are a big driving force in this locker room."

O'Reilly has a team-leading 17 goals and 40 points through 50 games. He plays in all situations, and leads Sabres forwards in averaging nearly 22 minutes of ice time per game. And, a week shy of his 25th birthday, O'Reilly is preparing to travel to Nashville to make his first NHL All-Star game appearance this weekend.

This is the type of production and leadership the Sabres were counting on in June when they paid a steep price to acquire O'Reilly and forward Jamie McGinn from the Avalanche in June. In exchange, Buffalo traded promising defenseman Nikita Zadorov, under-performing center Mikhail Grigorenko, prospect forward J.T. Compher and a second-round draft pick.

O'Reilly was the odd man out in Colorado because the Avalanche had difficulty meeting the player's hefty contract demands on a team already stocked with young forwards such as Matt Duchene, Gabriel Landeskog and Nathan MacKinnon. The Sabres didn't have such issues in their rebuilding-from-scratch process, and made O'Reilly Buffalo's top-paid player in signing him to a seven-year, $52.7 million extension in July.

For Sabres general manager Tim Murray, acquiring O'Reilly was something that had driven him since first taking over in Buffalo in January 2013.

For O'Reilly, the trade was the opportunity he was itching for since the Avalanche selected him in the second round of the 2009 draft.

"I think it's the change I needed in my life," he said. "I wanted a bigger role and to kind of be looked at as one of the top guys on the team. And here was that opportunity."

O'Reilly has topped 20 goals just once, in 2013-14, when he scored a career-best 28 times — six of them game-winners — and had 64 points in 80 games.

Bylsma, who was hired by the Sabres in May, acknowledged he didn't know much about O'Reilly in part because the Avalanche play in the west. He did get rave reviews about O'Reilly at the World Championships in the Czech Republic last spring. Penguins captain Sidney Crosby, whom Bylsma previously coached, and Sabres forward Tyler Ennis crowed about O'Reilly's work ethic in playing for Canada.

Bylsma is now getting a firsthand glimpse.

"He's come in and really been the heart and soul of our team," he said.

Bylsma credits O'Reilly's post-practice sessions for particularly helping the team's young players, including Buffalo's past two first-round draft picks Jack Eichel and Sam Reinhart.

"I don't have to wonder," Bylsma said referring to Reinhart, whose 12 goals rank third on the team. "A big part of Sam's development has been the work and the extra he's put in with Ryan."

In Colorado, Duchene isn't surprised by the impact his former teammate is making.

"He's an elite player, and he does a lot of things really well on both sides of the puck," Duchene said, noting O'Reilly has worked himself into the conversation to make Canada's roster for the 2016 World Cup of Hockey tournament.

The Sabres (20-26-4) have plenty of room for improvement. They're coming off consecutive last-place finishes and still showing the tell-tale signs of a rebuilding franchise.

Hovering near the bottom of the standings further motivates O'Reilly.

"I have to help lead that," O'Reilly said. "I know it's building blocks for us right now, but still, we want to win."

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AP Sports Writer Pat Graham in Denver contributed to this report.