The Islanders have been down a defenseman for much of this season and will be again for the foreseeable future.

The team placed Adam Pelech on long-term injured reserve with an upper-body injury Saturday after No. 3 played just 55 seconds in a 5-3 win over Ottawa on Friday night.

That means Pelech will be out for at least 10 games and 24 days, with his earliest return date being Dec. 19 against Edmonton. 

No announcement was made on the status of Sebastian Aho, who also left Friday’s game within minutes, ahead of Saturday’s match against the Flyers.

While Pelech is on LTIR, the Islanders can exceed the salary cap by dipping into the LTIR pool.

However, they will not accrue cap space towards the trade deadline.

Most likely, the immediate solution will be to insert Samuel Bolduc into the lineup and call up a defenseman from AHL Bridgeport, with Robin Salo, Grant Hutton and Dennis Colowski being candidates.

This amounts to a major test for the 22-year-old Bolduc, who has already played 10 games this season due to a prior injury to Pelech and Scott Mayfield being out.

The Quebecois has yet to earn the trust of Lane Lambert, who severely limited his ice time as Bolduc averaged just 9:38 per game heading into Saturday.

When Pelech was last out, Aho moved up to play with Dobson while Bolduc was paired with Scott Mayfield.

But with Aho’s status in doubt, it’s unclear whether that will be an option.