With all four matchups set in the Eastern Conference, here's a look at the key storylines that could help define each series:
Boston Bruins vs. Detroit Red Wings
The underdog Red Wings looked comfortable in the role of giant killer last spring, knocking off the second-seeded Ducks in a seven-game opening-round thriller ... and this year, they're primed to do it again. While they're up against a tougher opponent in Boston, they've given Bruins fits all season, taking three of their four meetings. More importantly, they've found ways to win games in which they were outplayed as they were in a 3-2 victory on April 2. The Wings can't match Boston's depth or playoff experience, but they have a knack for hanging around just long enough to take advantage of breaks with their opportunistic offense. If they can steal one early, they might work their way into the heads of the Bruins.
With Steven Stamkos out for much of the season, there's no denying who stepped up as Tampa Bay's MVP -- Ben Bishop provided the Lightning with the kind of goaltending they haven't had since Nikolai Khabibulin tended the twine. He finised among the league leaders in GAA (2.23, 7th) , save percentage (.924, 7th) and wins (37, 4th). But the big keeper missed the final three games of the regular season with a wrist injury, and there's no guarantee that he'll be fit for this series against the Habs -- or if can he come back for it at all. The drop-off to backup Anders Lindback is significant, and while Olympic hero Kristers Gudlevskis is an option, he'd be a bit of a Hail Mary with just one NHL start under his belt. Bishop has experience questions of his own -- he's never started an NHL playoff game -- but he clearly gives Tampa its best chance to advance. His status could swing the series.
All eyes will be on Marc-Andre Fleury and his efforts to prove that he can step up to the pressure of the postseason, but the one to watch in this one will be his teammate, Kris Letang. The fleet defenseman's game fell apart as completely, if not as glaringly, as Fleury's did last spring and he never quite found his footing this season before a stroke sidelined him for nearly three months. Letang returned just in time to get a taste of some game action before the playoffs, skating in two games to generally solid reviews. The Pens dearly missed his transitional skills and ability to kick start their offense this season. If he's able to move the puck effectively and limit the turnovers that plagued him early on, he could be the difference-maker in this set.
It wouldn't be Philly if the lead story wasn't goaltending. The health of Steve Mason is in question after the starter was involved in a nasty collision during Saturday's game against the Penguins, and while coach Craig Berube says Mason will be ready to go, the Flyers might be better off if he isn't. Mason hasn't played a postseason game since 2009, and his 0-4 record doesn't suggest that anyone in Philly should set aside some cash for round two tickets. But what if Berube played a hunch and went with backup Ray Emery? The veteran has a sterling record against the Blueshirts: 7-3-0 with a 1.87 GAA. Of course, he gave up four goals on 35 shots in his only appearance against them this season, a 4-1 loss on Jan. 12, and he's dropped four of his past five decisions this season, so ... yeah, goaltending could be a problem.