Players take note: Referees aren’t swallowing their whistles so far in the 2018 NHL playoffs.

Penalties are up more than 17 percent over the same time a year ago and are playing a substantial role in several series. Through 19 games in the first round, there have been nearly 10 penalties per game. Last year, there was an average of eight penalties called through 20 games.

“The penalties that have been called in the series so far is an indication of how the referees are calling the game,” Pittsburgh coach Mike Sullivan said today. “They’re calling it as they see it. I think discipline is of the utmost importance.”

While the two-time defending Stanley Cup champions haven’t been perfect in that regard against Philadelphia, they haven’t been derailed by a lack of discipline. Around the rest of the NHL, penalties and the ensuing power-play goals are making a big difference: There have been 38 power-play goals through Sunday’s games compared with just 21 in 2017.

The NHL wants officials to call playoffs at the same standard as the regular season, which is happening with penalties actually going up from the first period through the third. Each of the 10 pairings of referees working the playoffs has at least one who has worked the Cup Final, so the hope is having that experience helps maintain consistency.

The Washington Capitals blew two-goal leads in back-to-back overtime losses on home ice to Columbus because of ill-advised penalties and go into Game 3 on the road knowing it’s a problem that needs immediate fixing.

“We need to be a little smarter,” center Nicklas Backstrom said. “We need to play with better discipline — especially when we have the lead twice. … It’s obviously going to hurt you in the playoffs. That’s the way it is. It’s just fact.”

Nine of the 14 regulation goals in the Washington-Columbus series have come on the power play. The Blue Jackets, who surged into the playoffs by not taking a lot of penalties to tax one of the worst special teams units in the league, lead the playoffs in penalty minutes per game.

Coach John Tortorella said the Blue Jackets “have to cure that” because it’s too dangerous to keep taking so many penalties. His players know it even if they’re unsure of the standard.

“We need to stay out of the box, but you never know what’s a call and what’s not anymore,” forward Cam Atkinson said. “But that’s the game right now.”

In the West, where Winnipeg leads Minnesota 2-1, the teams realize how tight things are being called.

The Wild took five penalties in the first 31 minutes Sunday night and stymied the Jets’ power play in a 6-2 comeback win. The teams combined for 19 penalties — including some fights and misconducts — in the second game of their series.

“We’ve just got to watch taking penalties,” Minnesota coach Bruce Boudreau said. “Both teams were really emotional at the beginning and you’ve got to worry about taking penalties and getting behind the eight ball.”

It’s chippy between the Golden Knights and Kings, too, with Vegas up 3-0 going into Game 4 in Los Angeles. All three games so far have been decided by a goal, L.A. defenseman Drew Doughty was suspended for an illegal check to the head of William Carrier and Kings coach John Stevens is none too happy about a missed call on Vegas forward Erik Haula for hitting Anze Kopitar in the face with the butt end of his stick Sunday night .

“We get a guy suspended for making a hockey play, and he butt-ends one of the best players in the world in the face,” Stevens said. “That’s an intent-to-injure play.”