They were fresh off another Stanley Cup Playoff miss, had allowed a League-high 293 goals last season, and saw their captain John Tavares leave New York as an unrestricted free agent to sign a seven-year, $77 million contract with his hometown Toronto Maple Leafs on July 1.
It appeared the Islanders would be focusing on the 2019 NHL Draft Lottery, not the Stanley Cup Playoffs, at the end of the regular season.
But Trotz and the players had other plans.
"I said it early in the year, if you want to go somewhere quick, you go alone," Trotz said after New York clinched second place in the Metropolitan Division with a 3-0 win at Washington on Saturday. "If you want to go somewhere far, you go as a group. They decided to go as a group."
Video: #ThirstForTheCup: Islanders clinch a playoff spot
And they did so with a defense-first system, especially after Lou Lamoriello assured when he was hired as president of hockey operations one month prior to Trotz's arrival on June 21 the Islanders would correct the mistakes in their own end that were all too common last season.
Not only did Trotz fix the defense, he did so in historic fashion: New York became the first team in 100 years to allow the fewest goals in the NHL (191) one season after allowing the most.
So here the Islanders are, ready to host a Game 1 in the Stanley Cup Playoffs for the first time since 1988 when they play the Pittsburgh Penguins in the Eastern Conference First Round at Nassau Coliseum on Wednesday (7:30 p.m. ET; NBCSN, CBC, TVAS).
Video: Isles defeat Caps to clinch home-ice in First Round
"When you say 'culture change,' it's just a way of doing things," Trotz said. "We talk about accountability in some areas and the way we present ourselves, the way we act, the way we respond to adversity, all those things. That's part of changing the culture. Changing the culture might be instead of when things get a little bit rough in terms of maybe not going a certain way, if you don't have a great culture you fracture and you all go individually in your own direction, when actually you should come together and go in the same direction.
"That's a mindset. That's something day in and day out you force accountability on the guy next to you and he trusts you're going to get your job done."
The players quickly bought into what Trotz was preaching, and why wouldn't they? After all, he went 205-89-34 and qualified for the playoffs in each of his four seasons with the Washington Capitals, not to mention he is the reigning Stanley Cup-winning coach and arrived in New York as the fifth-winningest coach in League history with 762 victories.
You can add another 48 to that list after the Islanders finished fifth in the League standings with 103 points.
"They drilled it into our heads pretty early that we're going to be a defense-first team," said center Casey Cizikas, who scored an NHL career high 20 goals during the regular season. "That was the first thing that we had to clean up, especially coming off of last year.
Video: NYI@WPG: Cizikas taps home loose puck to tie game
"Everybody bought in. Nobody questioned it, nobody dropped their shoulders and sulked. They bought in and right away and they wanted to get better. We did that as a group."
Perhaps that's what makes the job Trotz has done this season even more impressive, considering 19 players on the Islanders roster played at least one game for them last season.
"We've got pretty much the same group and some real key additions," defenseman Thomas Hickey said. "But philosophy wise … I think you're always careful to say too much, because we have a lot of respect for the people that were here before, but the buy-in to the structure from our standpoint as players has been huge and simplified a whole lot of things.
"You can see why he's won a Stanley Cup and he goes far every year."
After saying throughout the offseason and the early part of training camp the Islanders likely wouldn't have a replacement this season for Tavares as captain, it was announced the morning of the season opener (Oct. 4) at the Carolina Hurricanes that forward Anders Lee was named the 15th captain in Islanders history.
Lee, who scored 40 goals playing alongside Tavares last season, scored 28 goals and 51 points this season without him.
Video: NYI@DET: Nelson dishes to Lee for power-play goal
"We've had a good room for years," said Lee, who was captain at the University of Notre Dame from 2011-13. "This room is a really good room. Everything's changed obviously since last summer, there's a lot of big, different things going on, moving parts, the culture that starts with Lou and Barry and his staff, and then down to us in the room when they're not around - holding guys accountable, being there for each other. The atmosphere's different, the feeling's different.
"You know what? These are the type of moments you want to be having every year. We want to be an organization that's consistent with that."
The leadership and vision of Trotz and Lamoriello have led to this improbable run by the Islanders to not only a playoff berth, but home-ice advantage for the first time in 31 years.
But the players know being here isn't enough.
"They don't accept complacency in any way whatsoever," left wing Matt Martin said. "They told us from the beginning that we were going to be a team, a good team. We just had to buy in. I think we've done a good job of that. We've played the right way."