These days, it is hard to score goals in the NHL. This holds true at even strength and also on the power play. Therefore, finding the right fantasy hockey players to fill out an entire roster can sometimes be difficult. Often times, fantasy leaguers like to stockpile players who contribute regularly on a team with a good power play which can be a winning strategy. That said, power play units are rarely stagnant from year to year. Changes in personnel, changes in systems and adjustments made by the opposition all contribute to variances in power-play percentage from year to year. Therefore, last season's struggling power plays can suddenly be the ones to track, while 2015-16's top power play units might fall back to the pack in 2016-17.

Variance is not limited to power-play teams either. Sometimes, players gain or lose significant time on the power play from one season to the next, which can often shift a player's overall fantasy value severely. There are teams that will, at times, utilize a defenseman considered to be a 'power play specialist', who sees most of his minutes with the man advantage. Quite often, however, he gets scratched from the lineup due to match-up situations thus reducing his overall fantasy value significantly. There is a lot of risk when looking for fantasy players based on their power-play ability because it is usually a very fluid situation.

The bottom line: power-play specialists might not be worth the hassle anymore. In 1977-78, the Montreal Canadiens set a record with a power-play percentage of 31.88%. Last season, the Anaheim Ducks led the NHL with a 23% success rate with the man advantage. That is a significant difference. Given the numbers and changes to the game, the importance of extra time on the power play may not matter as much as it was once perceived. That said, here are five players whose fantasy value could vary depending on his power-play ice time in 2016-17:

1. Andrew Shaw, W/C, Canadiens                                       

With Chicago, Shaw saw regular time on the power play (often with the top unit) due to his ability to take punishment in front of the net. In Montreal, that is usually Brendan Gallagher's job. Without significant power-play minutes, Shaw's fantasy stock could become negligible. He comes with much more fantasy risk now.

2. Ryan Nugent-Hopkins, C, Oilers

The Oilers were expected to trade Nugent-Hopkins in the off-season but instead moved left-winger Taylor Hall to New Jersey. Now, Nugent-Hopkins enters '16-17 with the possibility of serving a third or shutdown-line role in Edmonton. That could mean less even-stretch production, so Nugent-Hopkins needs to be on the first PP Unit.   

3.  Tomas Hertl, W/C, Sharks

For most of 2015-16, Hertl anchored the Sharks' second power-play unit and was limited to seven points with the man advantage. The talented Czech forward could supplant veteran Patrick Marleau on the No. 1 unit this season, which may push his fantasy value up several notches (though Hertl does not need the PP to produce).

4. Thomas Vanek, RW/LW, Red Wings

Vanek's days as an impact scorer appear to be over, and he may struggle to keep up with some of Detroit's young, speedy talent up front. That said, he can still produce on the power play (he placed fourth on Minnesota in PP points last season). The Wings probably signed him with the power play in mind, so he better produce.     

5. David Pastrnak, RW, Bruins     

Last season, Boston's power play improved significantly thanks in part to the utilization of their top three centers (Patrice Bergeron, David Krejci and Ryan Spooner) on the first unit. The addition of David Backes could push Pastrnak even further away from significant time on the power play which may hurt his breakout chances.