
The New Jersey Devils lost arguably their most important defenseman in Tuesday night's 3-2 shootout victory over the Pittsburgh Penguins.
In the first period at PPG Paints Arena, Jonas Siegenthaler lost an edge in the neutral zone and hit the boards. With the assistance of a trainer, he skated off the ice and did not return to the game.
"We are going to have to get him evaluated," Keefe said to NJD.TV. "He's going to miss time for sure, just not sure the extent of it."

The Devils have five healthy defensemen on their roster, along with Santeri Hatakka, who remains on injured reserve.
New Jersey will play two more games before the 4-Nations break, where no regular-season games will be played from Feb. 10 to 21. The Devils host the Vegas Golden Knights on Thursday before traveling north to play the Montreal Canadiens on Saturday.
Currently, the Devils are two points behind the Carolina Hurricanes and seven points ahead of the Columbus Blue Jackets in the standings. While Siegenthaler is being evaluated, the immediate goal is to survive the next couple of games and enter the break on a high note.
Hatakka was placed on injured reserve in early October after undergoing shoulder surgery in Vail, Colorado. His first practice with his teammates was on Jan. 21, where he skated as an extra.
On Jan. 24, The Hockey News asked Keefe what the plan was for the 24-year-old.
"I am not quite sure on the exact timeline," he said. "He is obviously progressing very well. [...] I think there is a plan to get him up and running in Utica at some point soon, but I am not certain when that is."
During the 4-Nations break, the Utica Comets (AHL) will play five games, allowing Hatakka to get some reps and re-acclimate to game-time speed.
If Siegenthaler requires additional time to recover, New Jersey's coaching staff can slide Hatakka, who plays the same side, into the lineup when the Devils return on Feb. 22 against the Dallas Stars.
In the short-term, and only examining the next two games, the Devils have a couple of options.
The first name that will come to mind is 2022 second-overall pick Simon Nemec. He is coming off an appearance at the 2025 AHL All-Star Classic and is riding a three-game point streak.
Nemec has spent time on the penalty kill and power play with the Comets. He has taken positive strides in his defensive game, showing more patience with the puck, not chasing the play, being on the right side of his check, and improving his box-outs.
His decision-making and when to offensively pinch in is one area that remains very inconsistent in his game.
Nemec plays the opposite side of the Swiss blue liner, so if he is called, one defenseman needs to play on their off-hand. It is not as challenging as it seems as there are benefits to defensemen playing on the opposite side.
It is no secret that Nemec was disappointed in not making the Devils roster out of training camp. The two games leading up to the break will allow the 20-year-old to showcase his defensive improvements, while rewarding his play in the AHL.

The other logical call-up would be 27-year-old veteran Colton White, who could seamlessly slide into the lineup on the left side. He has 84 games of NHL experience and plays a no-risk north and south game.
White has been one of Utica's top defensemen, with Seamus Casey saying, "He is an unbelievable hockey player, and I don't think he really gets the credit he deserves all the time."
The scheduling of the 4-Nations break allows the Devils to focus on the two upcoming games and re-evaluate their situation to determine how to move forward when the season picks up in a couple of weeks.
The most important thing is that whichever defenseman fills in over the next two games helps the Devils earn two victories. The team's schedule after 4-Nations is brutal, with road games against the Stars, Colorado Avalanche, and Winnipeg Jets waiting for them.
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