Cousins suffered a torn quadriceps muscle in Game 2 of the Warriors' first-round series against the Los Angeles Clippers on April 15. He returned from the injury in Game 1 on Thursday night.
Cousins replaced Jordan Bell in the starting lineup, who started in the first game of the Finals.
Cousins played eight minutes off the bench in the Warriors' loss in Game 1 versus the Raptors. He scored three points and added two assists and two steals. He was 0-for-2 from the field and 3-of-4 from the free throw line.
The four-time All-Star selection is tasked with guarding Toronto veteran center Marc Gasol, who scored 20 points in the Raptors' win Thursday night. Cousins has averaged 4.7 points, 3.7 rebounds and 2.3 assists per game in the playoffs.
The Raptors hold a 1-0 lead in the best-of-seven series.