Center Auston Matthews, the projected No. 1 pick of the 2016 NHL Draft, was not in the lineup Friday for Zurich in Switzerland's top professional league because of an upper-body injury, according to CAA Sports Agency, Matthews' representatives.
There was no timetable for how long Matthews will be out.
The injury casts into doubt Matthews' availability for the United States at the Deutschland Cup, which will be played Nov. 6-8 in Augsburg, Germany.
Matthews, an A-rated prospect on NHL Central Scouting's September players to watch list, has 10 goals, 16 points and 46 shots on goal in 14 games this season.
The 18-year-old forward may have sustained his injury Oct. 23 during a 3-1 loss against Fribourg-Gotteron when he fell hard into the boards and missed his next two shifts.
"It was during a puck battle when he did fall head-first into the wall," Central Scouting's Thomas Roost said. "He felt some pain and didn't show up for the next shift. But he did come back in that game."
Matthews had an assist and one shot on goal in Zurich's next game two days later, a 6-3 victory against SCL.