A rough night in Edmonton could turn into an even uglier stretch in New York, where officials at NHL headquarters are holding their breaths right now, but likely fearing the worst.

Connor McDavid, the overall No. 1 pick in the 2015 draft, suffered an upper-body injury that was described by coach Todd McLellan as "long term" following the Oilers' 4-2 win over the visiting Philadelphia Flyers.

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With the Flyers leading 2-1 and 1:44 remaining in the second period, McDavid was on a partial short-handed breakaway but fell awkwardly and was ridden hard into the boards by Philadelphia defensemen Michael Del Zotto and Brandon Manning, who also lost their balance on the play. Here is how the play unfolded at full speed.

McDavid left the ice favoring his left shoulder. He was seen wearing a sling in the hallway behind the dressing room and did not return for the third period.

The team announced after the game that general manager Peter Chiarelli would discuss the injury with the media on Wednesday morning. But that didn't prevent reports from getting out ... and those reports aren't good.

He had 12 points in his first 12 games and was named the NHL's Rookie of the Month for October.

-- The Associated Press contributed to this report