The reigning Stanley Cup champions received some terrible news Wednesday.

The Pittsburgh Penguins’ best defenseman, Kris Letang, will undergo surgery for a herniated disc in his neck and will be out for the next four to six months. He will miss the team’s 2016-17 playoff run.

Kris Letang will undergo surgery for a herniated disc in his neck. The recovery period is expected to be 4-6 months. https://t.co/Q3Fjb0wSkp pic.twitter.com/sSSezzNNIf

— Pittsburgh Penguins (@penguins) April 5, 2017

“Right now it’s hard to swallow,” Letang said to NHL.com. “It was not expected. Like I’ve done in the past, I’m going to put my energy into getting better.”

“Kris underwent an MRI in February that revealed a herniated disk in his neck,” Penguins General Manager Jim Rutherford said in a release. “Our neurosurgeons examined him and recommended conservative treatment in an attempt to correct the condition without surgery.

“Kris had been making progress and was hopeful of returning for the playoffs until about a week ago, when the progress plateaued. He underwent another MRI, and, at that point it was determined that surgery was needed.”

According to Peter Hassett, the Pens have not been the same team since Letang left the lineup on February 21. In the two months since, the Penguins have generated only 50.4% of the shot attempts and 50.7% of the expected goals. Letang is arguably the Penguins’ most impactful possession defenseman.

Letang is not the Penguins only injury concern. According to NHL.com, the Penguins are currently without seven regulars on top of their best defenseman.

The Penguins are without forwards Evgeni Malkin (upper body), Carl Hagelin (lower body), Chris Kunitz (lower body), Bryan Rust (lower body) and Tom Sestito (upper body), and defensemen Olli Maatta (hand) and Trevor Daley (knee). Sullivan said Malkin has been skating the past couple of days and is optimistic he’ll be ready for the playoffs.

The Capitals, who are one point away from clinching the first seed in the playoffs, will play the East’s second wildcard team in the first round of the playoffs. If they win, the Caps will play the winner of the Penguins and Columbus Blue Jackets series in the second round.