The deal will see misfiring Boro striker Kris Boyd move in the opposite direction to the City Ground.
With Jason Steele and Danny Coyne both injured, Boro boss Tony Mowbray has spent all weekend desperately trying to sign an experienced keeper ahead of tonight's game with Derby.
He all but admitted defeat yesterday evening, but early discussions this morning have paved the way for Smith's arrival.
The keeper is understood to be travelling to the North-East this morning in order to seal the deal, with Boro having until 4.45pm to register him for tonight's game.
Smith has not made a senior appearance since last May, however, so it remains to be seen whether he goes straight into the starting line-up for tonight's game.
Boyd's departure is hardly a surprise given Mowbray's reluctance to play the former Rangers striker, who was signed amid much fanfare by Gordon Strachan last summer It is likely that Boro are continuing to pay a significant proportion of Boyd's wages, which are understood to be more than ?30,000-a-week.
Source: Northern Echo
Source: Northern Echo