It is believed that Colback is hoping to complete the switch officially on his return from holiday.
But the Geordie boy seems destined to remain in the North East after talks with Aston Villa, West Ham United and Sunderland boss Gus Poyet, who tried to persuade him to stay after his contract expired.
Colback is a boyhood Newcastle fan, but slipped through the net for United after joining Sunderland at the age of 10.
However aged 24, Newcastle look to have won his services on a free transfer while he has his best years in front of him.
Sources close to Colback say that he was eager to make the right move at this stage of his career, and it is believed to have been offered a £10m package by West Ham.