The 23-year-old will spend the rest of the season at Sixfields after heading down from Ewood Park, with Northampton seeing off competition for his signature.
"Tyler is a centre-back who has a decent range of experience under his belt and is someone we have been tracking closely for some time," said Brady.
"He will give us the option of changing systems if we want to, he will provide competition to the other centre-backs, he will add depth to the squad and he has the attributes we are looking for.
"He has plenty of pace, he is very mobile for a centre-back and we are looking forward to welcoming Tyler to the club.
"He has had some other interest in him, including a club in League One who were very keen to sign him so we are pleased he is coming to Northampton Town."