Pittsburgh's captain played 22 regular-season games in 2011-12, missing the other 60 as he dealt with concussion-related issues. That came on the heels of missing the second half of 2010-11 and all of the 2011 Stanley Cup Playoffs for the same reason.
The good news for the Penguins is that Crosby was his usual self when he returned for good on March 15 -- he showed no ill effects and put up 37 regular-season points, as well as eight in Pittsburgh's six playoff contests. The bad news is he hasn't played a full season since 2009-10, and has played only those 22 games since going down with a concussion on Jan. 5, 2011.
Crosby isn't the only key player who's working to come back from an injury that put a hole in his 2011-12 season or ended it early. Here are seven other players whose return is critical to their teams' success.
Horton suffered a concussion in late January and didn't play again after Jan. 22 -- just seven months after he sustained a serious concussion in Game 3 of the Stanley Cup Final after a hit by Vancouver's Aaron Rome.
The Bruins -- and especially linemates David Krejci and Milan Lucic -- were not the same team without him. Boston was shut out five times in February and never showed the kind of consistency it had in the three previous months with Horton in the lineup, ultimately losing to the Washington Capitals in the opening round of the playoffs.
Horton, who finished with 17 goals and 32 points in 46 games, was cleared for contact late last month. If he's healthy, his return would be a major boost for the Bruins.
Green, like Crosby, has spent most of the past two seasons battling injuries that reduced him from an All-Star defenseman to a press box spectator on too many nights. A shoulder problem, concussion, ankle injury and lingering groin strain limited him to 81 games during the past two seasons -- he missed 50 games in 2011-12 largely because of the groin strain, which required sports hernia surgery.
The Caps still believe Green can be an elite player; they signed him to a three-year, $18.25 million contract this summer. Green said after his signing that there's no question he can go back to being the Norris Trophy finalist who had back-to-back 70-point seasons in 2008-09 and '09-10.
"One hundred percent and it will be next year," Green said when asked if he could return to his old form. "Absolutely, there's no question about it. I feel like I'm just getting into my prime."
Gagne's 2011-12 regular season ended early -- a concussion he suffered on the day after Christmas kept him out of the Los Angeles Kings' lineup the rest of the way, limiting him to seven goals and 17 points in 34 games.
Gagne was able to get into the lineup for the last four games of the Stanley Cup Final, but played fourth-line minutes as L.A. beat the New Jersey Devils to win the first championship in franchise history. He reportedly underwent offseason surgery to remove a small mass from his neck, but is already training for the upcoming season.
The 32-year-old has missed at least 19 games per season since 2007-08, mainly due to concussions and groin injuries. The Kings, who won the Cup after barely making the playoffs, could use his scoring touch.
The Oilers have been delighted with the progress they've seen from the first player chosen in the 2010 NHL Draft. They just wish he could stay healthy for a whole season. Hall missed the last few weeks of his rookie season due to a knee injury; his second season was cut short by a shoulder injury that required surgery -- and that came not long after he missed time with a severe facial cut from a skate blade during an accident in pregame warm-ups.
Hall improved from 22-20-42 as a rookie to 27-26-53 last season, despite playing four fewer games. He got back on the ice in early August, about four months after the shoulder operation, and the Oilers hope he'll be ready for a full season.
Like Gagne, van Riemsdyk was able to get back into the lineup for the playoffs after his regular season was ended by an injury -- in this case, a broken foot suffered while blocking a shot on March 1, capping an injury-filled season in which he managed just 11 goals and 24 points in 43 games. He missed seven weeks before returning for the Philadelphia Flyers' last seven playoff games.
The second player taken in the 2007 NHL Draft should be healthy for 2012-13 -- but he'll be wearing a new uniform this season after being traded to the Toronto Maple Leafs in a deal that sent defenseman Luke Schenn to the Flyers. Van Riemsdyk's six-year, $25.5 million contract will begin this season, and he could find himself being moved from the wing to center.
"It's something that will be a good opportunity for me, I think," he said. "I've played a little bit in the past and I think it's always good to be versatile as a player. I'm definitely excited about the opportunity."
Montreal's captain was on track for his seventh consecutive 20-goal season when a bicep injury intervened. He had eight goals and 15 points before his season was ended on Jan. 10 by a torn right bicep; he underwent surgery the following day. The injury came just three days after he had returned from a month-long absence due to a groin injury. He had hoped to return before the end of the season, but it didn't happen.
Though he's now 33, Gionta is still a reliable second-line scorer as well as the team leader. The Habs need to have him healthy and productive if they have any hope of returning to the playoffs.
Rask's season came to a sudden end on March 3, when he stretched to make a save against the New York Islanders and suffered a groin injury. It was an unfortunate finish to a season in which he had often outplayed reigning Vezina Trophy winner Tim Thomas, posting a 2.05 goals-against average in 25 games.
Thomas wound up playing every minute in the playoffs, which saw Boston lost to Washington in overtime of Game 7 in the first round. With Thomas deciding to take a year off, Rask is the No. 1 goaltender in Boston after signing a one-year deal. With no proven backup, the Bruins need Rask to prove he's healthy and that he can carry the load of being the starter for a team with Stanley Cup aspirations.