In the financial world, SEC regulations require mutual funds to inform potential investors that "past performance is not indicative of future results," per Forbes' John Brown.

Hockey fans should keep this concept in mind when they start forming their expectations for their favorite players and teams for the upcoming NHL season.

If we knew what was going to happen, fantasy sports would be no competition. If general managers could see into the future, every No. 1 draft pick would be the best player in his class.

In hockey, last year's losers can become next year's winners and vice versa. Some young players improve, while others fail to live up to expectations. Veterans start to tail off or defy the odds to remain effective. Injuries, trades, coaching changes, linemates and off-ice issues all become key storylines as the season unfolds.

Here is a look at eight players who are going into the 2017-18 season with the biggest question marks surrounding their situations. Some are looking to bounce back from injuries. Others will try to make good impressions in new surroundings. There are also those dealing with major uncertainty about what's next in their hockey careers.

Jonathan Drouin, Montreal Canadiens

The Question: Will Jonathan Drouin live up to expectations with the Montreal Canadiens?

What to Watch: With 21 goals and 53 points for the Tampa Bay Lightning last season, Drouin demonstrated the elite talent level that made him the third overall pick in the 2013 draft.

Back in January 2016, Drouin's agent, Allan Walsh, revealed his client had been asking for a trade since November.

Fences were mended, and Drouin became an important member of the Lightning last season. Nevertheless, salary-cap challenges and a chance to obtain promising defense prospect Mikhail Sergachev from the Montreal Canadiens prompted Tampa Bay general manager Steve Yzerman to deal the 22-year-old restricted free agent rather than trying to sign him to an expensive new contract.

After arriving in Montreal, Drouin signed a six-year deal with a cap hit of $5.5 million per season. On the ice, he'll be looked upon to replace the scoring of the departed Alex Radulov next season. The skillful winger is also being groomed to be Montreal's first French Canadian superstar since Patrick Roy left in a huff in December 1995. No pressure there!

Drouin has the talent to become a hero in the province of Quebec. It remains to be seen whether he'll be able to withstand the intensity of dealing with Montreal's unique dual-language media corps and a rabid fanbase that is desperate to see its team's 24-seasons-and-counting Stanley Cup drought come to an end.

Matt Duchene, Colorado Avalanche

The Question: Will Matt Duchene ever be traded?

What to Watch: In today's NHL, trades take time.

It took around 19 months for Drouin to see his trade request from the Lightning come to fruition.

Similarly, Elliotte Friedman of Sportsnet reported in November 2015 that the New York Islanders were trying to accommodate Travis Hamonic with a trade to his home base in Western Canada. That deal also took 19 months to consummate—Hamonic was dealt to the Calgary Flames on June 24.

So maybe the Duchene deal will still come to pass. In his offseason 30 Thoughts column, Friedman suggested a July trade may be possible and listed five teams that could be interested in acquiring Duchene's services.

Colorado Avalanche executive vice president of hockey operations Joe Sakic may be stubbornly sticking to his asking price, but if Duchene starts next season in the Mile High City, the meter will be running. The versatile forward has two years remaining on his contract, which carries a cap hit of $6 million per season, before he becomes an unrestricted free agent.

Nico Hischier, New Jersey Devils

The Question: Can Switzerland's first No. 1 overall draft pick make an immediate impact in the NHL?

What to Watch: Nico Hischier is following in some massive footsteps. For more than a decade, the first pick in the draft has immediately jumped to the NHL. The last time a player took an extra year to hone his skills was in 2006, when defenseman Erik Johnson spent one season with the University of Minnesota before joining the St. Louis Blues.

Since then, first picks like Patrick Kane, Nathan MacKinnon, Aaron Ekblad and, most recently, generational players Connor McDavid and Auston Matthews have all stepped seamlessly into NHL roles.

It sounds like Hischier will be following the trend, starting the season with the New Jersey Devils. Shortly after Hischier was drafted, Mike Fischer of NJ.com reported that Devils general manager Ray Shero said, "We have a spot for him, and we'll go from there. How's that?"

At the conclusion of the Devils' summer development camp, Shero doubled down, telling Mike G. Morreale of NHL.com that "[Hischier's] been everything I had hoped he would be."

In what was believed to be an underwhelming 2017 draft class, Hischier made a late charge in the rankings to claim that No. 1 spot. He'll get every opportunity to continue his upward trajectory and show he can continue the trend of first picks making big noise when they hit the NHL ice for their rookie seasons.

Jaromir Jagr, Free Agent

The Question: Will the 45-year-old Jaromir Jagr find work in the NHL in 2017-18?

What to Watch: Two days before free agency opened on July 1, superstar winger Jagr took to his Twitter account to let teams and fans know his services were available. After leading the Florida Panthers with 66 points in 2015-16, he dropped to 46 points last season, and the Cats declined to offer him a new deal.

Since then, Jagr's name has been tossed around by virtually every fanbase in the league. The NHL's second-highest scorer of all time, behind Wayne Gretzky, Jagr is an icon of the sport and in amazing physical shape. He told NorthJersey.com's Andrew Gross that he'd like to play until he's 55.

In the past, Jagr hasn't come cheap—including performance bonuses, he made $5.515 million with the Panthers last season. And while he has played for eight different NHL teams in his long career, he has never played in Canada and shown a preference for life in the Eastern Conference. Of 1,711 career games, just 34 were played in the West, with the Dallas Stars in the lockout-shortened 2012-13 season.

The longer Jagr remains unsigned, the greater the likelihood he'll have to drop his price and/or expand his list of landing spots if he's still determined to stay in the NHL next season.

If he doesn't catch on with a club, he'd have a chance to unretire from international competition and suit up for the Czech Republic at the Olympics in February—20 years after his national team's galvanizing gold-medal win in Nagano, Japan.

Erik Karlsson, Ottawa Senators

The Question: Can Erik Karlsson return to his amazing level of play after he recovers from foot surgery?

What to Watch: Karlsson had won two Norris Trophies by the age of 24, but last season, he earned a new level of respect in the NHL. Under new coach Guy Boucher, Karlsson unveiled a more complete playing style—now with shot blocking! He also put the Ottawa Senators on his back in the playoffs, getting the team within one goal of the Stanley Cup Final despite playing with hairline fractures in his left foot.

As it turns out, the fractures were only part of the problem. On June 14, the Senators announced that Karlsson had undergone surgery to repair tendons in his foot that had torn during the team's playoff run.

The Ottawa captain's recovery time after the operation was estimated at four months, which should put him on the ice near the beginning of the regular season.

Back in 2013, Karlsson proved to be a quick healer when he got back into action just 10 weeks after a skate cut lacerated his left Achilles tendon. The injury had been expected to keep him sidelined for three to four months, based on then-GM Bryan Murray's early timetable.

Hockey fans will be hoping not only that Karlsson won't miss too much time next season but also that these latest issues, which are affecting the same foot, will not harm the effortless skating stride that forms the nucleus of his game.

Patrick Marleau, Toronto Maple Leafs

The Question: How will Patrick Marleau look when he dons the Maple Leaf?

What to Watch: Auston Matthews has never known a world where Marleau was not a member of the San Jose Sharks. Drafted second overall in 1997, Marleau was barely 18 when he played his first regular-season game for the Sharks in October 1997, less than a month after Matthews was born.

The 37-year-old was part of the select group of players who had suited up for just one team during their careers—until he signed a three-year contract with the Toronto Maple Leafs on July 2.

It's not surprising the $18.75 million total value was enough to uproot the one-time Sharks captain. It also didn't hurt that the offer came from Toronto, a team that has quickly become competitive thanks to its dynamic group of talented youngsters. Coach Mike Babcock added to the appeal—the two were both part of Canada's gold-medal teams at the 2010 and 2014 Olympics.

After spending 19 seasons in one city, Marleau has a big adjustment to make. Not only is he expected to add scoring punch to the Leafs' top six as he skates beside speedsters like Matthews and Mitch Marner, but he'll also be under the microscope in the center of the hockey universe.

The old man will need to keep up—and he'll need to put up some scoring if he hopes to prove to Leafs Nation he's the mentor the team needs to claim a spot among the league's true Stanley Cup contenders.

John Tavares, New York Islanders

The Question: Will John Tavares re-sign with the New York Islanders, or will he become an unrestricted free agent on July 1, 2018?

What to Watch: Since back in the days of Sakic and Yzerman, NHL teams have done their best to re-sign franchise centers before they get a chance to test free agency.

During the summer of 2016, Steven Stamkos teased us with the possibility he'd sign with his hometown Maple Leafs before deciding to return to the Lightning. Now, all eyes are on Mississauga, Ontario, native Tavares.

With 537 points in 587 career games since entering the NHL as a 19-year-old first overall draft pick back in 2009, Tavares ranks in the top 15 in the league, with 0.91 points per game over eight seasons. But the Islanders have made the playoffs in just three of those years, and the team took a step backward last season, dropping back out of the postseason picture.

The Islanders acquired Jordan Eberle in June with the hope that he'll be an elite finisher on Tavares' right side—and that a successful pairing might entice the captain to stick with the team rather than test free agency.

The longer Tavares remains unsigned, the bigger the distraction will become.

Steven Stamkos, Tampa Bay Lightning

The Question: Can Stamkos stay healthy and regain his old form?

What to Watch: When Yzerman inked Stamkos to his eight-year, $68 million contract during the summer of 2016, he made his captain the highest-paid player on the Lightning and one of the wealthiest in the league.

But five seasons have passed since Stamkos won his second Rocket Richard Trophy with career highs of 60 goals and 97 points back in 2011-12. Granted, no one has come close to that mark since then—Alex Ovechkin came closest, with 53 goals in 2013-14. Stamkos also finished second in scoring in the lockout-shortened 2012-13 season behind teammate Marty St. Louis, with 57 points in 48 games.

Since the beginning of the 2013-14 season, Stamkos has missed 115 regular-season games and 16 playoff games because of a broken leg, blood clots and a torn MCL.

Over the past four seasons, he has averaged 0.92 points per game, but because he has suited up for only 213 games, his 196 points rank him 78th overall in total production during that time, tied with Jaden Schwartz and Radim Vrbata.

Stamkos is due for some good luck after all his health issues. If he can put together an 82-game season, it would go a long way toward helping the Lightning get back into the playoff mix in 2017-18.

All stats courtesy of NHL.com. Contract information from CapFriendly.