Crabb and Wilson joined the Capitals on Thursday. The Capitals-Rangers series is tied at two games apiece.
The Capitals needed a right wing after Martin Erat suffered an upper body injury in Game 4. Coach Adam Oates said Erat was undergoing an MRI and will probably miss Friday's game.
The 30-year-old Crabb had two goals and eight penalty minutes in 26 games with Washington this season.
The 19-year-old Wilson made his professional debut last week in the AHL playoffs. The No. 16 overall pick in the 2012 draft had one goal and six penalty minutes in three playoff games with Hershey.