Thompson is being sent down to AHL Rochester while in the midst of a 23-game goal drought. The 22-year-old has just seven goals and five assists for 12 points in 65 games this season.
Thompson's demotion Thursday comes a day after Buffalo called up rookie forward Victor Olofsson.
Olofsson is leading Rochester with 60 points. He has an opportunity to make his NHL debut Thursday, when Buffalo hosts Detroit.