Bylsma told reporters Crosby, who has been out of the lineup since Dec. 5, is performing light workouts but hasn't yet shaken the symptoms, the Pittsburgh Post-Gazette reported.
It was the first update on Crosby's condition since the player said Dec. 12 he was still having headaches despite passing concussion tests. He said then he was optimistic he would not be out for as long as he was when he missed 10 months between January and Nov. 21.
He played eight games for the Penguins before being pulled from the lineup again early this month.
The newspaper said it was unclear if Crosby was experiencing symptoms from the original concussion or had suffered a new injury.
Campus cop fatally shoots Texas student during traffic stop
Puzzle-maker slips 'Murdoch Is Evil' into Rupert Murdoch's Sunday Telegraph