Smart was medically cleared by doctors and participated in the Celtics' Tuesday morning shootaround. Coach Brad Stevens says he'll come off the bench and wear a protective splint.
Smart had surgery on March 16 to repair a torn ligament in his right thumb. He hasn't played in a game since March 11.
Smart's return should provide a lift to a short-handed Boston backcourt. With Smart out, Terry Rozier has been starting with Kyrie Irving ruled out for the playoffs following his second knee surgery. Reserve Shane Larkin has been playing extra minutes to support Rozier.
Prior to his injury, Smart was averaging 10.2 points, 4.8 assists and 3.5 rebounds per game.
In late January, Smart suffered a cut to his right hand as the result of a self-inflicted injury. He punched a picture frame in his Los Angeles hotel room during the team's road trip, causing an gash on the hand that required stitches and for him to be out of the lineup.
He returned to the lineup on Feb. 23 vs. Detroit and played in every game after that. Then, on March 11, Smart injured his right thumb again. Days later, the length of Smart's absence from the lineup was undetermined as he was reportedly seeking second opinions on how to treat the injury.
He then had the surgery on his thumb, which has sidelined him ever since.