The Capitals will face the Bruins in the playoffs for the first time since 1998.
The Capitals finish with the seventh seed and are expected to open the first round of the playoffs in Boston on Thursday.
Capitals coach Dale Hunter was vague when asked about the severity of Michal Neuvirth's injury.
The Capitals have a shot at their fifth straight division title. The Rangers are seeking their first Presidents' Trophy since 1994.