The 20-year-old will stay with the League Two side initially until January.BCFC
The 20-year-old will stay with the League Two side initially until January.
Left-back Seddon, who can also play wide left or at centre-half, was among the Blues substitutes for the Carabao Cup tie at Reading.
And he was promoted to the senior squad last season after impressing in the Under-23s.
Seddon, though, has yet to make his Blues professional debut but is on the fringes of a breakthrough.
Stevenage are ninth in League Two and face Cambridge United at home on Saturday.