The news that Pittsburgh Penguins' star Sidney Crosby will be sitting out of play indefinitely is leaving many worried that the hockey superstar's career might never be the same again – or even perhaps that it's coming to an end.

The 24-year-old announced Monday that he was benching himself after noticing a recurrence of post-concussion symptoms. Crosby sat out two games last week as a precaution after not feeling well following a game on Dec. 5. Now, he says the symptoms were still lingering during light workouts over the weekend.

Howard Bloom of Sports Business News says Monday's news spelled a dark day for hockey all around.

"The good news is he is taking every precautionary measure he can and he is sending the right message out that if you're injured and you've suffered a concussion, take the time to recover. What could it mean for Sidney Crosby? Well potentially, the end of this career," Bloom told CTV's Canada AM Tuesday morning.

As every hockey fan knows, Crosby took 10 months off after a devastating concussion last year, finally returning to play on Nov. 23. He appeared to be strong, scoring two goals and adding two helpers in his season debut.

But the Cole Harbour, N.S. native has not felt right since Dec. 5 when he bumped into the back of Bruins centre David Krejci, who then hit Crosby in the head with his elbow.

Most observers say the hit was "incidental contact" -- a typical hit that can happen several times a game. But Crosby has not played since, and there's no timetable for when he might play again.

Now, some are worrying that Crosby's career might be cut short like Eric or Brett Lindros, who both retired because of post-concussion syndrome. But TSN hockey insider Darren Dreger says it's simply too early to speculate.

"We don't know that, but the markers indicate that this is going to be a long-term issue," Dreger told Canada AM.

He added that it's heartening to see that Crosby and his team are taking his brain health seriously.

"Something that Crosby and the Penguins should be commended on is how forthcoming and upfront they've been in this process," he said.

Crosby told reporters Monday that the setback was frustrating, but he stressed he was being cautious and didn't want to take any chances with his recovery. He said he performed an athletic concussion test, called an ImPACT test and he passed. But he still doesn't feel right.

Many are wondering whether Crosby may have returned to play too soon and that his brain hadn't fully healed from last January's concussion. Dr. Charles Tator, a neurosurgeon at Toronto Western Hospital, says it's hard to say for sure, but that it's unlikely.

"There are a lot of unknowns about the management of concussions," he told CTV News Channel Monday night.

"Sidney is a very intelligent man and I think he waited long enough to give his brain a chance to recover. And now again, he's showing good judgment by waiting until he gets over these last effects," he said.

Tator notes it's well known that if someone with a brain injury returns to play too early, it can simply worsen the problem and force them to stay out even longer to get over any new injury.

He added it doesn't matter that Crosby wasn't hit very hard in that Dec. 5 game.

"Any blow to the head can make a difference to somebody who had had previous concussions," he said.

Bloom of Sports Business News says it's not just Crosby who's hurting with this latest setback; it's the NHL in general.

Crosby has the potential to be a very marketable brand name in the U.S. because he's so likeable and translates tremendously to the camera, Bloom said.

"It had to be a very bad day for Gary Bettman and company," Bloom said of Monday news.