Roy had surgery to repair a torn meniscus in his right knee two days before the start of the playoffs. Although the team initially said he would not be available for the first round, his recovery time was put at one to two weeks.
The three-time All-Star leads the Blazers with 21.5 points per game.
Roy was greeted with a hearty ovation during pregame warmups. He did not start, but was suited up on the bench. He entered the game with 4:06 left in the first quarter and made a layup about a minute later to put Portland ahead 20-19.
The Blazers, trailing 2-1 in the series, put forward Dante Cunningham on the inactive list with a stomach virus.
Eds: UPDATES with Roy entering game. CORRECTS Roy is a three-time All-Star, No pickup.