NEW YORK (CBSNewYork) — The Islanders’ defense has been much improved this season, but it will have to make due without one of its best players for a while.

The team announced on Friday that Johnny Boychuk was placed on injured reserve with an upper body injury. The rugged defenseman suffered the injury late in the third period of the Isles’ 2-1 win in Buffalo on Thursday night.

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The 31-year-old’s timetable for return is unknown.

Boychuk, who signed a long-term deal with the club late last season, appeared to injure his shoulder when he hit the end boards after missing a check on Sabres rookie Jack Eichel. He had been having a strong game up to that point, logging 18:41 of ice time and registering an assist, five shots on goal and two blocked shots.

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Though his offensive production is a bit down this season — three goals and 11 assists in 38 games — Boychuk has upped his physical game and has played a big role in the Isles allowing just 89 goals, sixth in the NHL.

Adam Pelech was recalled from AHL Bridgeport, but expect veteran Brian Strait to be inserted into the lineup. How head coach Jack Capuano will re-order his defense pairings remains to be seen.

Strait has a pair of assists and a minus-2 rating in 23 games this season, while Pelech, who is just 21, has appeared in just two NHL games, both earlier this season.

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The Islanders (21-12-5), who currently sit in second place in the Metropolitan Division, with the second-most points in the Eastern Conference, next play Saturday night in Pittsburgh.