PHILADELPHIA — Marshall Warren’s trust in himself is a quiet confidence without a hint of cockiness. But the Laurel Hollow product has no doubt he belongs in the NHL.

The 24-year-old defenseman backed his belief with two assists in his NHL debut as the Islanders lost a 4-3 shootout to the Flyers on Saturday afternoon at Xfinity Mobile Arena.

“I’m just doing my thing,” Warren told Newsday. “It took a while to get here but I know I belong and I feel like I’ve gotten overlooked a little bit. But I said when I get my chance I’ll make it meaningful. I think I did that job today.”

Warren, skating on the third pair with Tony DeAngelo after being recalled from the Islanders’ AHL affiliate in Bridgeport on Thursday, logged 11:20 with two hits, two giveaways and one takeaway to go with his two helpers.

Technically, he became the third native Long Islander to play a game for the Islanders after Port Jefferson’s Chris Ferraro (1999-2000) and Smithtown’s Kyle Palmieri (2021-present), though Richie Hansen (1977-79) grew up in Northport after being born in the Bronx.

Warren grew up an Islanders’ fan and was a sixth-round pick of the Wild in 2019 who played four seasons of NCAA hockey at Boston College and one more at Michigan. He’s in his second full season in the Islanders’ organization.

And he became the Islanders’ third rookie this season to score in their debut after No. 1 overall pick Matthew Schaefer and Russian free agent Max Shabanov.

“It’s very important,” coach Patrick Roy said. “We’ve got good, young guys and we certainly want to see them play. I just feel we have a really good mix. Good veterans, good young guys and I love to see young guys play, maybe because I was in junior [hockey] for a long time [as an owner, general manager and coach]. I think they deserve the chance to show what they can do.”

Warren, retrieving the puck into the left circle, found Anthony Duclair at the right post for a 2-0 lead at 6:15 of the second period. Max Tsyplakov tipped Warren’s blue-line blast for a 3-2 lead at 4:21 of the third period.

“I thought I scored,” Warren said. “I cellied [celebrated] a little too hard. But it was cool.”

He took the traditional rookie lap stylishly without a helmet and stepped on the ice for his first shift at 1:13 of the first period.

Warren managed to keep his emotions in check.

“Just keep it simple and let everything come to you,” Warren said. “I’ve got the tools. Once my game comes, I’ll probably surprise a lot of people.”

Warren estimated he had 30 family and friends attend his debut, including his mother and sister. His father was tending to Warren’s grandfather, who is in the hospital.

“I can’t wait to call [my father],” Warren said. “He’s my best friend.”

Andrew Gross

Andrew Gross joined Newsday in 2018 to cover the Islanders. He began reporting on the NHL in 2003 and has previously covered the Rangers and Devils. Other assignments have included the Jets, St. John’s and MLB.