There aren't many more frustrating parts of building an NHL roster than having a top prospect take longer than expected to develop.
General managers who show the right amount of patience with their best young players are often rewarded, but at the same time, it's up to these prospects to put in the work and effort required to reach their full potential.
These young players need two, three and sometimes four years to become NHL regulars, but at some point, it's time to move on if there's not enough progress being made.
Let's take a look at five prospects whose time is now or never.
There's no question that David Rundblad has the playmaking skill and puck-moving ability to be a quality offensive defenseman at the NHL level, but his lack of toughness and defensive talent makes him an unreliable player at this stage of his career.
In 38 career NHL games, the 22-year-old defenseman has tallied just seven points with a minus-five rating. As a team that plays a physical, defensive-minded style of hockey, Rundblad must become a better two-way player to earn a prominent role on a crowded Coyotes blue line that is loaded with young talent.
Rundblad will compete for a roster spot during training camp and the preseason, and if he fails to make the team, it wouldn't be unfair to call him a draft bust as a former first-round pick.
After playing in over 100 games between the NHL and AHL, it's time for Rundblad to make major strides in his development.
The Toronto Maple Leafs had high hopes for Joe Colborne after acquiring him in a trade-deadline deal with the Boston Bruins during the 2010-11 season, but the former first-round pick has yet to show the consistency expected of a top prospect.
The 23-year-old has the size, goal-scoring skill and playmaking ability required to be a No. 1 center, but he hasn't made a smooth transition to the NHL, despite having three full seasons of AHL experience. He also doesn't play with enough truculence and isn't making a ton of progress defensively.
Toronto lacks depth and top-tier talent at center, which gives Colborne a tremendous opportunity to play an important role down the middle in 2013-14. But as a player on a one-way contract, it's now or never for Colborne as a Leafs player. If he fails to impress during training camp, don't be surprised if the Leafs consider trading him before his value plummets.
Chris Kreider became one of the league's top prospects after a great performance in the 2012 playoffs. He came into the lockout-shortened 2013 season as a favorite for the Calder Trophy, but the 22-year-old never earned a top-six role with the New York Rangers because his defensive abilities weren't up to former head coach John Tortorella's standards.
The Boston College product played in just 23 games for the Rangers last season with two goals and an assist, while also being sent down to the AHL's Connecticut Whale multiple times. His development has been slower than expected, but with that said, there's no reason for Rangers fans to panic over his ability to succeed in the NHL.
As a power forward with great skating ability and phenomenal goal-scoring skills, it's time for Kreider to make his mark in the NHL as a dependable top-six winger.
Playing for a more offensive-minded head coach in Alain Vigneault should help Kreider's development, in addition to the power-play ice time that he's expected to receive as one of the team's most talented playmakers.
Nino Niederreiter was supposed to join John Tavares as one of the New York Islanders' franchise cornerstones when he was drafted with the No. 5 overall pick in the 2010 draft.
Despite having a lot of speed and offensive skill, Niederreiter never adjusted to the NHL game. The 21-year-old winger scored just two goals with only one assist in 64 games on Long Island. As a 19-year-old, he appeared in 55 games for the Islanders, but failed to earn much more than a fourth-line role, despite the team's lack of elite skill in the top nine.
After failing to meet the expectations of a high draft pick, Niederreiter was traded to the Minnesota Wild over the summer, where he joins Mikael Granlund and Charlie Coyle in a group of talented forward prospects expected to make a meaningful contribution this season.
Niederreiter should be a third-line winger with the Wild in 2013-14, but another disappointing season may result in him being a full-time AHLer for the foreseeable future. It's now or never for the Swiss forward.
The Winnipeg Jets have been extremely patient with Mark Scheifele after drafting him No. 7 overall in the 2011 draft, but another failure to earn a permanent spot on the NHL roster could put the 20-year-old forward into the "draft bust" category.
In 11 NHL games, Scheifele has scored one goal with zero assists. Despite having impressive size, he hasn't adjusted to the speed and physicality of the pro game very well.
With the Jets in dire need of a No. 1 center to lead the offense for many years to come, Scheifele is under a lot of pressure to not only make the team, but also have a Calder Trophy-worthy campaign.
As a team that finished 16th in goals scored and 30th in power-play percentage, Winnipeg needs a top-six center who can score goals and create quality scoring chances for the club's highly skilled wingers. Scheifele has the skill set required for this role, so it will be interesting to see if he takes the next step in his development this season.