The 23-year-old centre-back returns to Sixfields after a successful loan spell in the second half of last season. He made 10 appearances for Northampton and would have played more if not for a serious injury suffered against Bristol Rovers in March.
Magloire joins on a three-year contract after the two clubs agreed an ‘undisclosed fee’, although the majority of that is thought to come in various clauses and sell-on packages with minimal paid upfront.
The young defender made seven appearances in his time at Ewood Park, four of which were in the Championship last season. He also had loan spells with Rochdale, Hartlepool United and Motherwell before making the move to Sixfields.
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Magloire, Northampton’s 10th signing of the summer, is eligible to face Colchester United in Saturday’s opening game.