The Capitals will host the game four years after they visited the Penguins at Heinz Field in Pittsburgh.
Capitals owner Ted Leonsis is set to make the announcement at the team's fan convention Saturday.
It was not immediately clear which team the Capitals will play, though there is speculation it will be the Philadelphia Flyers, who hosted the 2012 outdoor game.
The NHL did not have any comment on the Capitals and their announcement Saturday.
It was not clear where the game would be played. Nationals Park is the most logical place, though RFK Stadium and FedEx Field, which is in Landover, Md., could also be options.