Harper will start Wednesday against the Rockets, Lachard Binkley of SI.com reports.
Harper has made just seven appearances for the Celtics this season and played a total of 35 minutes, but he'll get the starting nod Wednesday with Jaylen Brown (hamstring/knee) out. Joining Harper in the first unit will be Derrick White, Baylor Scheierman, Luka Garza and Neemias Queta.