The 19-year-old midfielder first joined the Romans from the County Ground in October for a month and then returned on December 9th until January 6th.
He made thirteen appearances for Bath in his two previous loan stints and scored 5 goals.
He has made sixteen first-team appearances for the Robins in the three seasons since he was handed his first professional contract in the summer of 2014.
Smith also spent the latter stages of last season out on loan with League of Ireland First Division outfit Waterford, scoring once in ten outings.