NEWARK, N.J. - One day after saying that Michael Leighton would return to practice Thursday, Flyers general manager Paul Holmgren revealed Tuesday that his No. 1 goaltender would be sidelined for at least a month with a bulging disk in his lower back.

In a conference call with reporters, Holmgren also said that forward Ian Laperriere would be out indefinitely with post-concussion symptoms.

On Monday, Holmgren said that an MRI exam had shown that Leighton had a lower back strain. However, the general manager said that Leighton consulted with doctors Monday night and Tuesday morning. That's when it was revealed that he actually has a bulging disk.

"It's unfortunate for the two individuals we're talking about today, Lappy and Michael," Holmgren said hours before the Flyers dropped a 3-2 exhibition decision to the New Jersey Devils at the Prudential Center. "They were both obviously big parts of our team at the end of last year."

Leighton was hurt Friday in the third period of a 4-3 shoot-out exhibition victory over the Maple Leafs in Toronto. The 29-year-old, who was not available for comment Tuesday, was removed after the overtime session and replaced by backup Brian Boucher for the shoot-out.

"Right now we think that time period is a month just to let everything settle down," Holmgren said of Leighton's injury.

He said the injury is more dicey for goaltenders than regular players because goalies spend so much time bent over in the net.

"My personal experience with a bulging disk is that they go back eventually," Holmgren said. "It's not a herniated disk, which is bigger in and of itself. It's a bulging disk, and we think with strengthening and rehab and time that he'll be fine."

Holmgren added that Laperriere, 36, has been dealing with post-concussion symptoms since last season. The right winger had an MRI exam on Tuesday and will fly to Pittsburgh to see a doctor on Friday. Laperriere will visit the same specialist he saw last season after suffering a brain contusion by blocking a shot with his face in Game 5 of the Eastern Conference quarterfinals against the Devils.

At that time, there was talk that his career was in jeopardy. Although he still experienced headaches, Laperriere returned a month later in time for Game 4 of the Eastern Conference finals against the Montreal Canadiens.

"I thought the summer would take care of it," Laperriere said. "I had some headaches here and there. But I would always find reasons - like, well, it's probably because I was dehydrated or because I worked out too hard today or I'm tired.

"It was always a reason. But I had to come down to [the fact that] it wasn't all those reasons."

The Montreal native said he didn't feel right in the first exhibition game with the Devils. He watched Friday's game from the press box, and the next day, he informed Holmgren of his symptoms. Laperriere said he would not play again until he is 100 percent.

"I'm just glad that I made that decision," he said. "I could have kept going and really injured myself out there."

Holmgren said Laperriere's status would not determine whether the organization signs right winger Bill Guerin to a contract. The veteran Guerin is in training camp on a tryout.

Holmgren also said he did not plan to make any moves to acquire a goaltender. Boucher is expected to beat out newcomer Sergei Bobrovsky as Leighton's replacement.

"The other guy who hasn't been in the equation yet is Johan Backlund," Holmgren said of the goalie who is recovering from off-season hip surgery. "We are hoping that he's going to be OK to play one of the last two [exhibition games], if not both of the last two games."

Backlund participated in his first practice Monday.

Holmgren added that the salary cap will not impact his decision on goalies.

"Because of the bonus cushion, Bobrovsky's [salary-cap] number would be $900,000," he said. "Bouch's is $925,000 and Johan's is $800,000, and Michael's is $1.55 million. So I don't think finances are an issue. What we decide, either way, it will work."

Flyers coach Peter Laviolette said before the game that injuries offer an opportunity for other players to step up. "You have to make the most of these opportunities when you get them," he said.

Devils left winger Ilya Kovalchuk made the most of his opportunity. He scored the winning goal with 2 minutes, 19 seconds remaining.

Boucher stopped 25 of 28 shots.

Guerin suffered a cut to his right elbow in the second period and did not return. Holmgren said the injury wasn't serious.

Contact staff writer Keith Pompey at 610-313-8029 or kpompey@phillynews.com.