The focus of hockey fans during the 2013 NHL playoffs will primarily be on the performance of superstars and goaltenders, but it's often someone you don't expect to come through in a key moment that turns the tide of a series.
X-factors are players whose performance will have a huge impact on their team's success during the playoffs. If these guys fail to play at a high level, their teams could be headed for an early summer vacation.
These players could be superstars, role players or guys who struggled during the regular season and are expected to raise their game once the playoffs commence.
Let's look at every playoff team's X-factor heading into opening round.
One of the best trade deadline acquisitions this season was the Pittsburgh Penguins acquiring veteran center Jussi Jokinen from the Carolina Hurricanes.
The 30-year-old forward has one more season on his contract with a $3 million salary cap hit, and his poor production offensively in the first half of the year likely prevented general managers from claiming him off waivers before the trade deadline.
Penguins GM Ray Shero decided to make a deal for him anyway, and it has given his team incredible depth down the middle and another reliable scorer.
Jokinen has nine points (five goals, four assists) in nine games with the Penguins, and his goal scoring, playmaking and playoff experience could play a major role in the team's success in the postseason. He's also good on faceoffs, especially in the defensive zone.
If Sidney Crosby is unable to play in Game 1 after recovering from a jaw injury, Jokinen will need to play well and contribute offensively in a top-six role for head coach Dan Bylsma.
It's difficult to predict which Milan Lucic will show up for the Boston Bruins in the playoffs.
Lucic was terrible offensively for most of the season (just two goals since February 24) and has not played with the level of physicality and grit that we normally see from the young power forward.
He played so poorly in the final quarter of the regular season that Bruins head coach Claude Julien scratched him on April 20 when Boston played the Penguins at TD Garden. Julien rarely benches his veteran players, but with Lucic failing to give the Bruins a physical presence on the ice and some much-needed goal scoring, it was a move that had to be made.
When the 24-year-old winger moves his feet and skates well, he can dominate games in all three zones with his toughness and scoring ability. His teammates feed off of the energy and passion he brings to the ice each shift, so it's important that Lucic brings his A-game in the playoffs. When he plays poorly, the Bruins are a much easier team to beat.
Lucic played more physical (including two fights) and created a lot of scoring chances in the final few games of the regular season, which was encouraging for Bruins fans, but he still has plenty of room for improvement in his game.
Braden Holtby was the Capitals' most important player in last year's playoffs because of his impressive play in net and composure in high-pressure situations. He was the main reason why Washington upset the defending Stanley Cup champion Boston Bruins in the first round, and he nearly led the team to the Eastern Conference Finals.
Following a 1-4 start to this shortened season, Holtby finished with a 23-12-1 record to help the Capitals make a late-season climb up the standings to win the Southeast Division and secure home-ice advantage in round one.
The Capitals finished fourth in goals scored and had the best power-play percentage in the league during the regular season, but for this team to make a deep playoff run, Holtby must play well consistently and give his team confidence.
Michael Ryder has Stanley Cup-winning experience, scores a lot of goals and plays an important role on the power play. With that said, his performance will be a key part of the Montreal Canadiens' success in the playoffs.
He was fantastic in his first few weeks with Montreal after being acquired in a trade with the Dallas Stars in February. Ryder tallied 14 points in 14 games after joining the Canadiens lineup, but he's only scored three goals in April (12 games).
The Canadiens lost five of their last eight games to finish the regular season and will play a strong defensive team in the Ottawa Senators in the first round of the postseason, so it's very important that Ryder provides them with the timely goal scoring that made him a key player in the Bruins' Stanley Cup run in 2011.
Mikhail Grabovski was a disappointment for the Toronto Maple Leafs this season with just 16 points (nine goals, seven assists) in 48 games.
In his last 15 games, the 29-year-old center has scored just one goal with two assists, which is not the production expected from a player that makes an average of $5.5 million per season (via Capgeek).
For the Leafs offense to score enough goals against the Boston Bruins and their star goaltender Tuukka Rask, they need Grabovski to create scoring chances for his teammates with the playmaking and creativity that has made him a quality NHL player.
When he plays well offensively, the Leafs have good depth down the middle and are more effective on the power play.
Brad Richards was disappointing for most of this season, but he improved mightily in April with 15 points in his last 14 games. He had two nice assists in the Rangers' 4-0 victory over the New Jersey Devils on Saturday, and New York will need his playmaking in the postseason.
This is the Richards that the Rangers need to show up in the postseason for this team to make a deep run to the Stanley Cup Final.
The veteran center is so important to the team's offense and power play because of his passing skills and creativity with the puck. No player on the Blueshirts does a better job of creating scoring chances for teammates when Richards is playing well.
With Richards being more productive offensively, the Rangers went 10-3-1 in April to secure a playoff spot. When he provides scoring on a consistent basis in addition to his contributions as a leader and a former Stanley Cup champion, Richards has a tremendous impact on the Rangers' success.
The New York Islanders had the seventh-highest scoring offense in the NHL this season, but they will only go as far as starting goaltender Evgeni Nabokov takes them in the playoffs.
The veteran netminder had an impressive 23-11-7 record for the Islanders, a team that struggled defensively in the first half of the year and finished 21st in GAA.
Since New York has to play the Pittsburgh Penguins, a team with fantastic scoring depth, in the first round, Nabokov needs to play at a high level for his team to have any chance of an upset.
The Isles will need to win in Pittsburgh at least once to win this series, and the team should be confident in its ability to win away from Nassau Coliseum due to Nabokov's 14-3-3 road record.
With a team-leading 80 games of playoff experience, the Russian goaltender's performance will have the most impact on the Islanders' postseason success.
Erik Karlsson suffered a 70 percent tear of his Achilles in February and was expected to miss the entire season following surgery, but he made a remarkable recovery and returned to the ice on Friday night. In his first game back, he played over 27 minutes and tallied two assists.
The Senators have great goaltending and a superb penalty kill, but they had a lot of trouble scoring goals this season. The absence of first-line forwards Jason Spezza and Milan Michalek, along with Karlsson's injury, greatly affected this lack of offensive production.
Now that Karlsson has returned, the Senators' power play will be greatly improved, which gives Ottawa a stronger chance to upset the Montreal Canadiens in the first round.
The reigning Norris Trophy winner is a tremendous skater, his playmaking skills are world-class, and he also scores goals. His offensive talent will significantly strengthen the Senators offense, which is a huge boost for them entering the opening round because they are the lowest-scoring (27th in goals scored) club in the 16-team playoffs.
Brandon Saad will likely be a Calder Trophy finalist this season because of his impressive offensive production and strong defensive play. The 20-year-old winger tallied 27 points (10 goals, 17 assists) in 47 games, while also blocking 12 shots with 26 takeaways.
His two-way game has been an important part of the Chicago Blackhawks' success this season, and he played well enough to earn ice time alongside Jonathan Toews and Marian Hossa on the team's top line.
The Blackhawks cannot be too reliant on its top forwards (such as Toews, Hossa and Patrick Kane) in the playoffs, which means that role players such as Saad will need to make an impact at both ends of the ice.
It's tough to predict how rookies will handle the intensity of the playoffs, but Saad has handled expectations well this season with the mental toughness and maturity needed to be successful in high-pressure moments.
He has the potential to be an impact player for the Blackhawks on what could be another Stanley Cup run for the Original Six franchise.
The Anaheim Ducks will not make a deep playoff run without quality goaltending from 30-year-old rookie Viktor Fasth, who had an impressive 15-5-2 record (including four shutouts) in his first NHL season. Following an 8-0-0 start to the year, Fasth cooled off a bit with a 7-5-2 record in his last 14 starts.
There will be a lot of pressure on Fasth in this year's playoffs, and it will be interesting to see how he handles it. The Detroit Red Wings are a tough first-round opponent because of their scoring depth and Stanley Cup-winning experience, and they will make a strong effort to test Fasth early and often throughout the series.
Anaheim will challenge the Blackhawks for the Western Conference title if Fasth gives his team a chance to win on a consistent basis during the playoffs.
Playing in the postseason won't be a new experience for Cory Schneider, but entering the first round as the starting goaltender for a team expected to make a deep playoff run is a position he's never been in during his NHL career.
The 26-year-old star finished the regular season with a 17-9-4 record (11-4-1 in his last 16 games) with a .927 save percentage and a 2.11 GAA.
He did well to establish himself as the undisputed No. 1 goalie in Vancouver, but this is the time of year when the pressure to win games really becomes a factor. This team's championship window is closing because some of its best players, including top-line forwards Henrik and Daniel Sedin, will not be in the prime of their careers for much longer.
Since the Canucks have an elite goaltender with lots of playoff experience in Roberto Luongo sitting on the bench, Schneider will not have much room for error in the opening games of his team's first-round series with the San Jose Sharks.
Schneider has played well in the postseason throughout his brief career, but the pressure of being the No. 1 goalie will be an adjustment for him. To prove that he's the goaltender of the present and future in Vancouver, Schneider needs to be one of the Canucks' best players during the playoffs.
If that happens, the Canucks will have a strong chance to reach the Stanley Cup Final because their goaltending has the ability to make up for the team's inconsistent performance offensively and struggles on the power play.
Brian Elliott helped the Blues win the William M. Jennings Trophy last season as the team with the best GAA, but his performance in the playoffs, specifically in the second round against the eventual Stanley Cup champion Los Angeles Kings, was not up to par.
The veteran goaltender had a 3.25 GAA in that series versus the Kings, which was a real surprise given how well he played in the regular season.
After a poor start to the year (3-6-1 record in his first 10 starts), Elliott finished strong with a 10-2 record in 12 starts in April. He's playing his best hockey of the season right now, which will be great for his confidence going into the opening round.
Since the Blues offense has been inconsistent this season (it ranked 17th in goals scored), this team will need strong goaltending to make a deep playoff run. As the team's No. 1 goaltender, St. Louis will go as far as Elliott takes it.
Hockey fans on the East Coast might not know a lot about Jake Muzzin, but the rookie defenseman is quickly becoming one of the most important players on the Los Angeles Kings blue line.
Injuries to key defensemen from last year's Stanley Cup run like Willie Mitchell have forced Kings head coach Darryl Sutter to play Muzzin an average of 17:54 of ice time per game, and the rookie has made the most of his opportunity.
Muzzin is tied for first in goals scored (seven) and tied for third in points (16) among rookie defensemen this season, and he also played well in his own end with 69 hits and 29 blocked shots.
For Los Angeles to repeat as Stanley Cup champions, it needs to play the same physical style of hockey that was so successful in last year's championship run. Muzzin's two-way game, toughness and ability to contribute on special teams will play a major part in the Kings' success during the playoffs.
Brent Burns' decision to switch positions and play on the wing after being a defenseman for most of his NHL career has proven to be a great move for his career, and it has allowed him to better use his impressive offensive talents to help the San Jose Sharks score goals.
He has an accurate shot, a quick release, great speed and a high compete level, so it's no surprise that 28-year-old veteran has been productive offensively as a forward.
Burns' production (nine goals and 11 assists in 30 games), most of which has come at forward, has given the Sharks more scoring depth and another difficult player for opposing teams to defend in San Jose's top six.
For the Sharks to beat a Canucks team in the first round that has great goaltending with Cory Schneider and Roberto Luongo (Vancouver ranked ninth in goals against), they need secondary scorers such as Burns to contribute offensively and be effective on the power play.
If San Jose has to rely too much on its top stars like Thornton, Patrick Marleau and Logan Couture, this team will fail to get past the first round for the second consecutive year. Special teams will be a major factor in this series, which will make Burns' role on the Sharks very important.
The Detroit Red Wings have a good chance to upset the Anaheim Ducks in the first round as the seventh seed in the Western Conference playoffs.
But for an upset to happen, the Red Wings need secondary scoring from players like Valtteri Filppula. At times this season, Detroit has been too reliant on star forwards such as Pavel Datsyuk and Henrik Zetterberg, who ranked first and second on the team in scoring, respectively.
Filppula has tremendous offensive skill and the ability to score 20-plus goals in a full 82-game season. The problem with Filppula is that he's too inconsistent, which makes him a frustrating player to watch because he's got all the talent needed to be a quality top-six forward.
He has to show up in this series and contribute offensively, especially on the power play, for the Red Wings to beat a Ducks team that has three lines capable of generating offense.
Filppula scored just nine goals in 41 games in this shortened season, which is below the expected level of production for a player with his kind of talent.
For the 29-year-old veteran to earn a lot of money as an unrestricted free agent in the summer, he needs to play at a high level in the playoffs and provide the scoring that Detroit will need from its second and third lines.
The Minnesota Wild gave up two quality prospects and their first-round pick in a strong 2013 NHL draft to acquire star winger Jason Pominville from the Buffalo Sabres at the trade deadline for additional scoring depth in the playoffs.
Minnesota barely made the playoffs despite losing three of its final five games. In that span, the Wild averaged just 1.6 goals scored per game and converted on just one power-play opportunity.
For the Wild to upset a Chicago Blackhawks team in the first round that is arguably the favorite to win the Stanley Cup and ranks second in goals scored, they need Pominville to provide timely scoring and offensive skill to the top-six forward group.
Pominville has not played since he took an elbow to the head from Los Angeles Kings captain Dustin Brown on April 23 (Brown was suspended two games for the elbow), but he did skate with the team on Monday (per the team).
If he is healthy and plays in this series, Pominville will need to score goals and contribute to the power play because without at least two productive lines, Minnesota will get swept or eliminated in five games.
The Blackhawks have the ability to shut down the Wild's top line of Zach Parise and Mikko Koivu by having their top defensive pairing of Duncan Keith and Brent Seabrook on the ice whenever that duo hops over the boards, so it's important for players like Pominville to give Minnesota some much-needed scoring depth in the playoffs.
Nicholas Goss is an NHL lead writer at Bleacher Report. Follow him on Twitter. He was a credentialed reporter at the 2011 Stanley Cup Final and 2012 NHL playoffs in Boston. All quotes obtained firsthand.