Siegenthaler (undisclosed) was hurt in the first period of Tuesday's game versus the Penguins, Sam Kasan of the Devils' official site reports.
Siegenthaler fell awkwardly after receiving a hit and retreated to the locker room. He didn't return at the start of the second or third periods, which suggests he is done for the game despite the lack of an update from the team. The Devils currently aren't rostering an extra defenseman, though Kurtis MacDermid has previously played on the blue line despite being deployed as a forward this year. If Siegenthaler can't play Thursday versus the Golden Knights, the Devils may need to make a roster move.