The 6-foot-7 center played for the first time since suffering the head injury in Game 5 of the Eastern Conference quarterfinals April 21. He centered the team's third line between Ruslan Fedotenko and Brandon Prust.
Before he was sidelined, Boyle tallied three goals in the first three games of the team's first-round series against the Senators.
Boyle skated for the fourth straight day Monday after sustaining the concussion.
The Rangers were 3-0 without Boyle.
With Boyle back in the lineup, defenseman Steve Eminger was scratched after he played briefly as a forward on Saturday in New York's 3-1 win over Washington in the series opener. However, forward Brandon Dubinsky sat out his second straight game because of a leg injury.
The Capitals made one lineup change, reinserting defenseman Jeff Schultz for John Erskine, who played in Game 1.
Information from The Associated Press contributed to this report.