No longer the coziest position in sports, backup goaltending duties are a proving ground for marginal players. Don’t expect these stalwarts in net to let their ice time fade once they are more than a stopgap measure. Exhibit A: Robin Lehner. After sitting the Islanders first two games of the season, Lehner wrestled control over the 1A role from Thomas Greiss, finished top five in save percentage and goals against average and won the first two games of the playoffs for the Islanders.

But Greiss was just as good. He, too, finished top five in the same statistical categories and helped turn Nassau Coliseum into the Islanders’ personal underworld where an opponent’s offense goes to die. Lehner and Greiss, with the ferociousness of the three-headed Cerberus at the gates of Hades, prevented a deluge of goals and sparked the Islanders’ transformation from the worst defensive team a year ago to the league’s best.

The stalwart tandem isn’t unique to the Islanders (see: Tuukka Rask and Jaroslav Halak in Boston), and neither is the dilemma it presents. When both goalies play so well, who gets the starting nod? There’s no wrong choice. Trotz never publicly announced which goalie he’d start, and he let Lehner know privately only a day prior. Calgary Flames coach Bill Peters took a similar public approach with David Rittich and Mike Smith (Smith was ultimately the starter). Two-headed situations are becoming the norm and it’s something that the NHL might see more of: Since the 2006 season, the top 15 goalies are averaging six less starts per year.

“There’s no doubt that there’s more pressure on the goalies today from the standpoint of the game is a little bit more open now,” says current NBC analyst Brian Boucher and former 13-year goaltender with seven different teams. “It’s not an easy position. Whether it is physical or mental, there are times when goalies need the break. We’ve seen a lot of it this year, that teams have confidence in two guys to get the job done. We’ll have to see how the coaches manage that come playoff time. That’s the tricky part.”

For right now, at least a few coaches have their answer. St. Louis Blues coach and former goaltender Craig Berube will ride Jordan Binnington, who overcame a Winnipeg whiteout, stonewalled Mark Scheifele in the final minutes and parlayed his stellar final 30 regular season games into an opening victory on the road. Sorry, Jake Allen. Ben Bishop is locked into the starting role over Anton Khudobin for the Dallas Stars. And barring injury, there’s no way the Predators’ Pekka Rinne will cede time back to Juuse Saros.

Trotz has his answer, too. It’s Lehner. He’s not only turned around his career, but the 27-year-old goaltender battled mental illness and recovered from substance abuse before the season began. Away from the doldrums of Buffalo, Lehner established himself as Trotz’s playoff starter. Greiss, too, rebounded on the ice and put the worst year of his career in the past. The Islanders’ duo was nobody’s breakout pick, but it has worked.

“All year they’ve been there, it doesn’t matter who starts,” Isles defenseman Ryan Pulock says. “They’ve been fantastic for us. It definitely gives us that confidence knowing that we have that behind us.”

Lehner adds, “If I didn’t play well in stretches I probably wouldn’t have played as much, and same with him. It’s good that we both play good.”

Choosing which goalie to go with is a “problem” more in the spotlight now because the best players at the position aren’t—or shouldn’t be—expected to hog 85% of the team’s starts. Steadfast netminders Martin Brodeur and Miikka Kiprusoff used to constantly log 70-plus games a year for their teams. That’s dying off—n the 2007-08 season, there were six goalies who started at least 70 games; there were zero in the last two seasons, and one in 2016–17—and goaltending situations are swinging back to the style of the 80s and early 90s.

“We try to do a 50–30 split,” says Red Wings goaltending coach Jeff Salajko. “We played Jimmy Howard a lot out of the gate the first half and we’ve discussed potentially playing Jonathan Bernier a little more in the first half next year.”

Salajko adds, “I know Jimmy can still play those 55-or-so games, but at what expense? Do you hit a wall in the second half? Are you risking injury? The game has changed. Goalies have to deal with a lot more in terms of net-front traffic and the speed of the game itself.”

The ideal is the Islanders’ situation, where both goaltenders feed off one another’s performance and thrive with healthy competition. One added bonus: cap space. In an era where team’s top offensive players are garnering $10-million-plus contracts, a two-headed monster in net can free up money to spend elsewhere. Petr Mrazek and Curtis McElhinney provide the Carolina Hurricanes slightly above-average goaltending for a combined $2.35 million cap hit, or just under 3% of a team’s salary cap limit. The Islanders duo comes in at around $5 million, as does the Blues.

Not all tandems are on equal footing, though, and some are borne of injury. Casey DeSmith, the Penguins backup, played his way to a three-year contract extension while Matt Murray sat on the injured-reserve list. It’s a boon to freshness when a backup plays well and can provide time for the starter to recover, especially considering netminders will usually have to play around 20 or more games on top of a 82-game season to claim the Stanley Cup. Now Murray is back and he’s gobbled up all the starts, leaving DeSmith sitting alone in the tunnel for the first two games of the playoffs.

And Murray, maybe more than anybody, knows how short the leash can be: After the hot hand, Marc-Andre Fleury, surrendered four goals in Game 3 of the 2017 Eastern Conference Final, Murray took over and piloted the Penguins to their second consecutive championship. The tandems that emerge out of the hot-hand approach cause more headaches when, suddenly, the hot hand turns ice cold. Circle starters Tuukka Rask and Mike Smith as potential victims with Jaroslav Halak and David Rittich ready and able if their series turn sour.

Meanwhile, Lehner took his seat in the locker room after a steadfast Game 1 performance. His face is coated with sweat and flushed with exhaustion, successful in warding off Sidney Crosby and Evgeni Malkin from escaping the barn with a victory. For two games, at least. To the rest of the other starters with a capable backup? Good luck.