Roundtable: Even series leaders like the Predators, Lightning and Blue Jackets have issues

Maple Leafs need to shut down Bergeron line again (2:00)

Greg Wyshynski previews Thursday's matchups including the Maple Leafs looking to even the series against the Bruins. (2:00)

What's the biggest trouble sign for a team that is leading a series?

Greg Wyshynski, senior writer: The Nashville Predators finished just 0.03 goals-against per game behind the Los Angeles Kings, who edged them out to win the Jennings Trophy, which is given to the team with the fewest goals scored against it during the regular season. Pekka Rinne is going to win the Vezina for top goaltender. Nashville's top four defensemen are the envy of the league. So why, then, have the Predators gone from a 2.49 GAA during the regular season to a rather-bloated 3.25 in the postseason? Especially when their team GAA during their run to the 2017 Stanley Cup Final was a minuscule 2.18?

The Predators are only plus-1 goal at even strength against a Colorado Avalanche team that finished 22nd in 5-on-5 scoring in the regular season. Granted, the Preds have been able to outgun the Avs despite being a bit leaky defensively. But if they have designs on the Stanley Cup, they'll need to tighten up that defense before playing someone like the Jets in Round 2.

Emily Kaplan, national NHL reporter: I'm worried about how many penalties the Tampa Bay Lightning are taking. It's not cause for alarm -- yet -- but it troubles me that Tampa Bay has drawn a whopping 21 penalties through its first four games, including 15 minors. Consider Monday's Game 3, when the Lightning had a chance to put the New Jersey Devils in a 3-0 series hole, but committed five minor penalties in the third period alone, including a check-to-the-head penalty by Mikhail Sergachev. We've seen an uptick of whistles in all the series this postseason; according to The Associated Press, through 19 games, penalties were up 17 percent from this time last year.

While the Lightning shined in so many areas during the regular season, the penalty kill was not one of them (28th in the league at 76.1 percent). In fairness, Tampa Bay did lose one of its best penalty killers, Ondrej Palat, for a large chunk of time. Moving forward, the Lightning can't allow games to slip away because they are sloppy or undisciplined.

Ben Arledge, NHL Insider editor: Yes, the Vegas Golden Knights swept the Los Angeles Kings. Yes, we all once again discounted how good of a hockey team Vegas has. But yes, the Golden Knights really struggled to score goals in the opening round.

They have averaged just 1.75 goals per game and 1.53 per 60 minutes, lows among teams either through the first round or currently favored to move on to the next round. According to Natural Stat Trick, Vegas has created 29 scoring chances per 60 minutes, ninth among playoff teams, and it has 32.8 shots per game, so the Golden Knights' scoring drought is not because of a lack of opportunity. They just can't capitalize on much. As a group, they are shooting just 5.7 percent at 5-on-5 (Vegas' second-round opponent, the San Jose Sharks, have a .979 5-on-5 save percentage), and the power play is fetching just a 8.3 percent success rate, better than only the Kings. No one on the Vegas roster has more than one playoff goal thus far.

You can survive like that against a team like Los Angeles that doesn't score and relies on a couple of primary guys to find the back of the net, but that lack of scoring support won't stand up against just about any team positioned to move on. Think one or two goals will be enough to win against the Sharks, Winnipeg Jets or Nashville Predators? It's not uncorrectable (William Karlsson tallied 43 goals this season, and four others broke the 20-goal mark), but it's definitely something that needs to be addressed soon if Vegas wants to continue this Cinderella season beyond the second round.

Sachin Chandan, ESPN the Magazine researcher: The Columbus Blue Jackets took two games in Washington before dropping Game 3 to the Washington Capitals on Tuesday night, but the red flag could be the type of games they've played. Each game in this series has gone to overtime. Because of this, the second-youngest team in the playoffs has been taxed with many high-leverage minutes.

Columbus defenseman Seth Jones leads all players this postseason with 32:42 average time on ice and 42 shifts per game. Cam Atkinson, Pierre-Luc Dubois and Artemi Panarin each average more than 27 minutes a game. Those three OT games were exciting for us, but they added 47 extra minutes for Blue Jackets goalie Sergei Bobrovsky. Columbus has been shorthanded 17 times, most in the playoffs, and has allowed the Capitals to fire 34 shots -- again, the most in the playoffs. The Blue Jackets had the third-best win percentage (at .622) in one-goal games this year, but these minutes under duress can add up against a team like the Capitals.