HITC Sport understands Blackburn set to sign loan star on permanent basis.
Downing joined Rovers on a season-long loan deal on transfer deadline day in the summer and he has made 18 appearances during the first half of the season for the club.
The 26-year-old has impressed at Ewood Park since his arrival and the club have decided to end his loan stay and sign him on a permanent basis.
MK Dons are willing to let Downing move on and the central defender is happy to make the move to Ewood Park full time.
Rovers boss Tony Mowbray is a big fan of Downing, having worked with the defender during his time in charge of West Bromwich Albion.
Mowbray sees Downing as playing a key role at Ewood Park for the forseeable future, and his signing on a permanent basis is a boost as the club looks to maintain their push for promotion back to the Championship.
Blackburn are expected to be busy in this month's transfer window, as money has been made available for Mowbray to strengthen the squad for a real push at automatic promotion.