Rodwell continued his rehabilitation from a persistent hamstring problem as City's elite development squad took on Oldham Athletic at Boundary Park.
Oldham named first-team manager Lee Johnson in midfield but he was unable to prevent Rodwell from opening the scoring on 21 minutes with an accurate header.
A powerful finish from close range after the break made it two for Rodwell, with Spanish youth international Denis Suarez adding a third for City soon after.
Rodwell completed his hat-trick from the penalty spot in the closing stages and also went on to play the full 90 minutes.
City ran out comfortable 4-0 winners on a night which also saw Micah Richards complete 90 minutes in defence to aid his rehabilitation from a long-term injury.