Evgeni Malkin could miss up to 10 games in his first NHL season with Pittburgh after dislocating a shoulder.
The rising Russian star collided with team-mate John LeClair in a pre-season game and will be out for 4-6 weeks.
Malkin was making his much-anticipated debut after his controversial departure from Russia to join the Penguins.
The 20-year-old rookie centre is not expected to need surgery, but will be watching from the sidelines when the new NHL campaign begins on 5 October.
Malkin remains at the centre of a bitter dispute between the NHL and the Russian Ice Hockey Federation.
He was widely regarded as the best player not in the NHL until last month when he left Russian club Metallurg Magnitogorsk to join the Penguins.
Metallurg Magnitogorsk have threatened legal action in a bid to seek compensation from the Penguins and the NHL.