Peterson was called up from AHL Springfield on Saturday.
Dillon Dube (neck) and Alexey Toropchenko (upper body) have landed on injured reserve since the season started, so Peterson will serve as a reinforcement to the Blues' forward depth. He had 24 points over 57 regular-season outings with Springfield last year. The 24-year-old forward will likely see bottom-six minutes if he gets into the lineup.