PITTSBURGH -- The tests indicate Sidney Crosby doesn't have a concussion. Crosby's body isn't quite so sure.

The Pittsburgh Penguins superstar said Monday he's dealing with a recurrence of concussion-like symptoms and is out indefinitely.

Crosby, who missed more than 10 months after taking shots to the head in successive games in January, hasn't played since developing a headache following a 3-1 loss to Boston last week.

"I ended up skating the following day after with a little bit exertion and it just didn't feel right," Crosby said. "After kind of talking with everyone it was better to be cautious here and not take any chances."

The 24-year-old former MVP passed an ImPACT test -- designed to diagnose concussions -- last Wednesday but didn't travel with the team on a road trip through Philadelphia and New York over the weekend.

Instead he remained in Pittsburgh hoping to play when the Penguins host Detroit on Tuesday, but those plans were scuttled when symptoms popped up over the weekend during what he called "light exertion."

Crosby stressed it wasn't back to square one but acknowledged it could be awhile before he plays. Though he is encouraged by the ImPACT results he allowed "the ImPACT isn't everything. You've got to listen to your body on these things too."

It's unclear if one specific hit caused the symptoms to resurface, though Crosby pointed to a first-period collision with Boston's David Krejci as significant.

Krejci was digging for the puck in front of the Pittsburgh bench when Crosby closed in. The Boston forward spun just before Crosby arrived, with Krejci's left elbow appearing to knock Crosby off-balance as play continued.

Crosby didn't miss a shift, playing more than 21 minutes as the Penguins fell to the defending Stanley Cup champions.

"I know I got hit in the head there," Crosby said. "But I felt like I was pretty good after that. I didn't feel like it was anything too major but if you look at one hit ... that was a good one."

Pittsburgh coach Dan Bylsma refused to place the blame on Krejci but on the cumulative wear-and-tear that comes over the course of a game.

"Right afterwards there was a little jostling between the two," Bylsma said. "Krejci gave him a little shove away. I didn't see that hit or that situation until after the game ... (but) he had some other hits as well."

Crosby has 12 points in eight games but hasn't scored since finding the net twice in his electrifying debut against the New York Islanders on Nov. 21. The Penguins are 5-2-1 this season when their captain plays but have grown accustomed to going without him over the last year.

"It's disappointing but you know, you want him to be 100 percent," forward Pascal Dupuis said.

Despite the setback, Crosby insisted he didn't feel "bad," just a little off. He went through a painstakingly slow rehabilitation after being diagnosed with concussion-like symptoms in January. He doesn't believe he's anywhere close to that situation.

He will, however, have to follow similar protocols. Crosby joined the Penguins at the start of training camp but spent more than two months practicing before getting cleared to play.