The underdog New York Islanders threw a scare into the heavily-favored Pittsburgh Penguins before falling to the Pens in six games.

Having been a league laughingstock for years, few gave the Isles much chance against the talent-laden Penguins. Led by rising superstar John Tavares, however, the Islanders used their speed advantage to exploit the Penguins weak defense and Marc-Andre Fleury’s shaky goaltending, winning two games and narrowly losing two others in overtime.

The Islanders served notice this season they are to be taken seriously as a playoff contender, but whether they build upon this or slide back into irrelevance depends upon their upcoming off-season moves.

Impressive as the Islanders performance was against the Penguins, they had defensive issues of their own, much of it due to playoff inexperience of blueliners Travis Hamonic, Andrew MacDonald, Thomas Hickey and Brian Strait. They needed an experienced shutdown defenseman against the Penguins.

Management must decide upon the future of veteran defenseman Mark Streit, slated to become an unrestricted free agent this summer.

Contract talks with Streit broke off before the trade deadline, prompting speculation he might walk via free agency.  Now that their season is over, both sides could renew talks. If they fail to re-sign Streit, a skilled replacement must be found via the trade or UFA market.

Goaltending is also an issue. Evgeni Nabokov played well enough during the regular season, but he appeared shaky at times against the Penguins, being pulled twice in the series in lopsided losses. One gets the impression coach Jack Capuano kept returning to Nabokov because he lacked faith in backup Kevin Poulin.

Nabokov is a UFA this summer, while Poulin is a restricted free agent. If the Isles decide to bring back Nabokov, they’ll need a more reliable backup who can be groomed as his successor.

Ignore the talk of the Islanders trading for Roberto Luongo. They learned their lesson after signing Rick DiPietro to a long-term expensive contract, which they’re expected to dump via compliance buyout this summer. They won’t take on the remaining 9 years of Luongo’s salary, even if the Canucks agreed to pick up half of it.

If they chase a goalie, targets could include LA’s Jonathan Bernier, Anaheim’s Viktor Fasth or St. Louis’ Jaroslav Halak. They might also consider dipping into the UFA market for someone like Jose Theodore or Ray Emery.

Apart from Nabokov and Streit, their other notable UFAs include Brad Boyes, Marty Reasoner, Keith Aucoin and Radek Martinek, while Hamonic, Poulin, Josh Bailey and Thomas Hickey are their notable RFAs.

Of these, Hamonic and Bailey are certain to be re-signed, and I believe they’ll keep Boyes if he’ll agree to an affordable short-term deal.

With over $35.3 million invested in 14 players, the Islanders have sufficient cap room to retain their key free agents and bolster their depth in goal and on the blueline. It remains to be seen, however, if ownership is willing to make the necessary investment.