Crosby, right, missed ten months last season due to concussion sustained in two different games [GALLO/GETTY]

Pittsburgh Penguins captain Sidney Crosby continues to experience concussion symptoms, raising questions about whether he will return to the National Hockey League (NHL) this season.

Crosby, who missed nearly an entire year before returning to action last month, was back on the sidelines after just eight games after absorbing another hard hit.

He complained of headaches and Pittsburgh coach Dan Bylsma said the problem still existed.

"He (Crosby) is still having symptoms," Bylsma told reporters following practice on Wednesday.

Crosby has not practised since December 7 but Bylsma confirmed that the Penguins captain had resumed light exercise but there was no indication on when he might return.

It was expected the Canadian would follow the same steps he did in his first comeback, returning to practise first before engaging in contact work.

The 24-year-old, the league's biggest draw card, absorbed two hits to the head in successive games on January 1 and January 5.

Crosby celebrated his comeback in dazzling style on Nov. 21, scoring twice and setting up two other goals as the Penguins pounded the New York Islanders 5-0.