Fairly sure it will be resignalled into Tyneside ROC. The line currently has 3 old-style boxes left, Newsham, Bedlington South and Bedlington North, at the loop and junction with the Morpeth line. I would expect that staffing 3 boxes is acceptable for the odd freight, but would be seen as not suitable for a full passenger service.
Signalmaps, an unofficial site, is showing a projected layout for the new Ashington workstation at Tyneside ROC:
https://signalmaps.co.uk/#ashington:1442. This suggests that the line is also gaining an extra passing loop, further pointing towards full resignalling.