Blyth played for 80 minutes and scored the winning goal on his return from the thigh injury that cut short his stay at Sixfields as the Foxes Under-21 side beat Blackburn 1-0 on Monday night.
The 21-year-old joined the Cobblers at the start of August on an initial month-long deal which was then extended until November 2.
However, he suffered a thigh injury in training towards the end of September and returned to his parent club to receive treatment.
Having recovered from the problem, Northampton boss Aidy Boothroyd is keen to have Blyth back and it is understood that will happen in time for the FA Cup first-round tie at Bishop's Stortford on Sunday.
Blyth scored three goals in eight appearances for the Sky Bet League Two club prior to his injury.