The team made the announcement about 25 minutes before the game at the Nassau Coliseum.
Following the Islanders' 2-1 loss to the Devils, an Islanders spokesperson said Capuano had been admitted to Long Island Jewish Hospital and was expected to rejoin the team later this week.
The team did not have an updated diagnosis on Capuano's condition.
Assistant coach Doug Weight ran the bench for the Islanders.
Capuano had been at the Coliseum for much of the day. He met with the media during the Islanders' early skate in the morning.