Over the first nine days of the NHL season, teams are averaging 3.05 goals per game, according to hockey-reference.com.

If that rate holds, it would mark the first time teams have climbed above three goals per game since 2005-06.

Here are theories for why scoring is up in the early going:

Youth movement: Sixty-eight rookies have played this season. That’s 10.3% of all players. After watching the Pittsburgh Penguins soar in last spring's playoffs, teams aimed to replicate them in being younger and faster. Skillful youngsters, such as the Toronto Maple Leafs' Auston Matthews and Mitch Marner or the Columbus Blue Jackets’ Zach Werenski, boast elite scoring touches and quicken the game's pace. But less experienced players make mistakes, and mistakes lead to goals.

World Cup bump: Stars are playing with mid-season sharpness because they were competing at a high level in September at the World Cup of Hockey. Look at Brent Burns, Brad Marchand, Joe Pavelski, Connor McDavid and Matthews, among others.

Goalies struggling: Jonathan Quick suffered a long-term injury, and Carey Price missed time with illness. Brian Elliott has slumped early in Calgary. Ben Bishop and Martin Jones are still searching for last season's level. The league save percentage of .903 is well below the .915 average of the past two seasons.

More power plays: Teams are averaging 3.68 opportunities per game. Last season, it was 3.11. We haven’t seen this level of penalty frequency since 2009-10. Are referees calling the game tighter, or are players fouling more because they are scrambling to keep up?

It’s anomaly: The season is not even two weeks old. World Cup participation meant training camps weren’t the same, and now the schedule is more condensed. Players are temporarily out of rhythm. In short order, defenses will tighten, goalie play will steady and scoring will be back to the levels it has been at for the last few seasons. By mid-season, the scoring rate for each team will be between 2.71 and 2.75 per game, the rate it's been for the past five seasons.