One of the most challenging aspects of putting together a winning NHL team in any given year is goaltending. Even if you’ve assembled a strong group of forwards and blue liners, all that can be undone if the last line of defense doesn’t hold up its end of the bargain.

Poor goaltending sinks the hopes of otherwise solid teams every year, and it’ll happen again during the upcoming season. There are only a select few goalies in the league capable of posting a .920-plus save percentage consistently in a starting role, and that leaves the remainder of teams to find other options and hope for the best.

During this offseason, four teams in particular were aggressive in addressing their goaltending after major issues last season. They all missed the playoffs last spring despite having a lot of talent on their rosters. In each case, low save percentages were a prime culprit for the lack of success.

Thus began the goaltender carousel this summer as those franchises sought out new talent to solve their woes. None of these teams managed to land a surefire stud, but there’s reason to believe that all four could see improved performance between the pipes next season. If that happens, watch out for these clubs.

2016-17 SV% ranking: 27th (.901)

New addition: Scott Darling

Darling is one of the most interesting players in the NHL. His hockey career was nearly derailed in his early 20s by alcohol abuse issues, but he managed to get his life on track before emerging as one of the best backup goalies in the league with the Blackhawks.

Over the past three seasons, Darling was exceptional with a .923 save percentage over 75 games (64 starts). His percentages swung around a bit over the years, going from .936 to .915 to .924, but the general baseline set here is that of a legit NHL starter.

Set to become an unrestricted free agent this summer, the Blackhawks accepted that he’d be moving on by trading his rights to the Hurricanes for a third-round pick. Carolina quickly signed Darling to a four-year deal worth $4.15 million annually that clearly established him as its new starter.

Last season, the Hurricanes’ goaltending was a mess behind Cam Ward and Eddie Lack. Ward posted a below-average .905 save percentage as the primary starter, and Lack was even worse at .902 in backup duty.

Now the team will likely go with Darling as starter and Ward as the backup, which should lead to upgrades in both spots on the depth chart. With the Hurricanes already boasting a talented young team that drove possession and had an elite penalty kill last season, Darling could be the final piece to push them into the postseason.

2016-17 SV% ranking: 30th (.894)

New addition: Ben Bishop

The Stars poured a ton of money into goaltenders over the past few years between Kari Lehtonen and Antti Niemi, but got a very poor return on the investment. Last season, those two earned a combined $10.4 million in salary cap space to be the worst goalie tandem in the entire league.

Enter Bishop, who was acquired from the Kings in the spring before the Stars signed him to a huge six-year deal worth $4.917 million annually. The 30-year-old is coming off a down year split between the Lightning and Kings, but he’ll be a massive upgrade in Dallas if he can return to form.

Prior to his 2016-17 struggles, which led to Andrei Vasilevskiy taking his job in Tampa Bay before he was traded in L.A., Bishop had a three-year run with the Bolts in which he posted a .922 save percentage over 186 games. In 2015, he helped power the team to the Stanley Cup Final with a .921 save percentage in 25 games.

So there’s a track record of above-average performance here, even if Bishop was below-average with a .910 save percentage last season.

Yes, the six-year term could be a problem down the road for the Stars given Bishop turns 31 in just a few months, especially if last season was a sign of what’s next. But for a team that can roll Tyler Seguin, Jamie Benn, Jason Spezza, Alexander Radulov, and Martin Hanzal in its top six, now is the time to win. Bishop should give Dallas a much chance than Lehtonen or Niemi did.

2016-17 SV% ranking: 26th (.901)

New addition: Brian Elliott

There’s a lot to like about the Flyers entering next season. They have Claude Giroux and Jakub Voracek still in their 20s at the top of the roster. Nolan Patrick should make his debut, and Travis Konecny could be ready for a breakout. Sean Couturier and Wayne Simmonds remain fantastic supporting forwards on high-value deals. Shayne Gostisbehere and Ivan Provorov even lend some hype to the back end.

But the real wild card is what’ll happen in net for Philadelphia. Last season’s Steve Mason-Michal Neuvirth pairing was a total mess. Now, the team has brought in the veteran Elliott, whose save percentages in the past two seasons are .930 and .910, respectively.

Whether the Flyers get the Good Elliott or the Bad Elliott could go a long way toward determining how successful they are. They’re otherwise an intriguing team with a ton of potential up front.

2016-17 SV% ranking: 28th (.900)

New addition: Steve Mason

Not too long ago, we wrote about why this could be the year the Jets return to the playoffs. They have a fierce top of the roster with Mark Scheifele, Patrik Laine, Nikolaj Ehlers, Blake Wheeler, Dustin Byfuglien, and Jacob Trouba leading the way. The offense should be one of the league’s best.

Changes in goal were another prime reason for optimism. Last year’s netminding duo of Connor Hellebuyck and Michael Hutchinson, with a sprinkling of Ondrej Pavelec for good measure, was terrible. Hutchinson and Pavelec in particular were bad, posting a combined .899 save percentage in 36 appearances.

Now the Jets have Mason, who was part of the Flyers’ struggles last year but could be primed for a bounceback season. The nine-year veteran saw his save percentage dip to .908 (which still would’ve led the Jets), but he was at .921 in 166 appearances over the previous three seasons.

Even if Mason cannot get back to the .921 save percentage he posted from 2014-16, it’s fair to believe that he’ll be a upgrade on what the Jets had before. And with Hellebuyck bumping down to the backup spot, replacing the need to use Hutchinson and Pavelec, Winnipeg should also get better effort from its No. 2 goalie than it did last season.

Like with the other three teams, it’s no sure thing that a Mason-Hellebuyck combination will be a grand success. But all four of these teams were aggressive in making sure they didn’t come back in 2017-18 rocking the same look. There’s a good chance that at least a couple of them take major leaps forward next season.