NEWARK, N.J. -- Sidney Crosby will be out at least six weeks for the Pittsburgh Penguins after having surgery to repair a core muscle injury Thursday, and his teammates said they have no alternative than to move forward without him.

"We have [a] great group here, everyone, we need to work … harder, every shift," center Evgeni Malkin said. "Be a leader on (the) ice and off (the) ice (and in the) locker room. I understand coach [Mike Sullivan will] give me more time to play. Everyone is looking to me right now. I need to play smart, it's not the first time I'm here without Sid, but I'm ready. It's nothing new for me."

Crosby could miss as many as 18 games before possibly returning to the lineup Dec. 26.

Malkin was playing center on the top line between Jake Guentzel and Bryan Rust during practice for the Penguins, who prepared for their game against the New Jersey Devils at Prudential Center on Friday (7 p.m. ET; ESPN+, SN, MSG+, ATTSN-PT, NHL.TV).

It will be the second straight game without Crosby for Pittsburgh, 4-1-2 in its past seven games, including a 3-2 overtime loss at the New York Rangers on Wednesday.

Video: Hradek breaks down Crosby's play on Guentzel's goal

The 32-year-old leads the Penguins with 17 points (five goals, 12 assists) in 17 games but has no points in his past four games.

Crosby had 100 points (35 goals, 65 assists) in 79 games last season, the first time he reached 100 since he had 104 (36 goals, 68 assists) in 2013-14, when he led the NHL in scoring and won the Hart Trophy voted as NHL MVP for the second time.

The No. 1 pick in the 2005 NHL Draft, Crosby won the Stanley Cup with Pittsburgh in 2009, 2016 and 2017. He ranks second behind Mario Lemieux for most goals (451), assists (782) and points (1,233) in Penguins history. He has played 960 games, the most in Penguins history, 45 more than Lemieux.

"Sid is a world-class player and he brings a lot of special things, so everybody here has to up their game a little bit," Rust said. "We're going to try and collectively make up for his absence."

Pittsburgh (10-6-2), which is fourth in the Metropolitan Division, went 8-5-0 in October despite a slew of injuries.

Video: BUF@PIT: Malkin wires home wrister for PPG

Malkin missed 11 games with a lower-body injury, and forwards Alex Galchenyuk and Nick Bjugstad each missed nine games with a lower-body injury. Rust didn't play in the first 11 games because of an upper-body injury, and defenseman Brian Dumoulin missed four games with a lower-body injury.

"We've dealt with injuries before, and guys stepped up and played big roles and did some special things," Rust said. "I think if we kind of keep that same mindset going forward, we'll be good."

Bjugstad, who has one goal in nine games this season, said everyone needs to contribute more.

"Sid is nonreplaceable," Bjugstad said. "It's got to be from everyone here. We have to work as a group and understand five guys on the ice can do it together, and if we're on the same page and buying into each other, I think we can be all right.

"We showed when we had a few injuries earlier in the season, where guys stepped up, younger guys came in and really showed their worth. I think we've got to just keep it simple and there's no reason this group can't continue to keep rolling."

In addition to Crosby, the Penguins are also without defenseman Kris Letang (lower body) and forward Patric Hornqvist (lower body). Letang has missed the past three games and is week to week, and Hornqvist has missed four games and is out longer term.

"Sid's a guy we look to a lot when things aren't going well and he's a guy who always steps us for us on the ice," center Jared McCann said. "We can't sit here and sulk. We need guys to step up. We still have a lot of games left here and just have to remain focused, keep grinding. We've had a lot of injuries this year but can't use that as an excuse. We just have to keep battling and remain focused."

This is the first time Crosby will be out a significant amount of time since he missed 61 straight games between the 2010-11 and 2011-12 seasons because of a concussion and neck injury sustained in the 2011 Winter Classic against the Washington Capitals on Jan. 1, 2011. He returned to the Pittsburgh lineup 11 months later, on Nov. 21, 2011, but was sidelined again in early December with a concussion until returning for good March 15, 2012.

He has played at least 75 games each season since the start of 2013-14.

The Penguins said Crosby had been playing through a sports hernia he sustained in training camp.

"He's a real tough kid. And he's got a passion for the game," Sullivan said. "He plays through a lot, always has in my experience coaching him here, so it doesn't surprise me."