The move is being driven by Sunderland's new goalkeeper coach, Neil Cutler. He previously worked with Johnstone at Aston Villa and Wolves, which could be an advantage in the recruitment process.
It is likely that Sunderland would sign Johnstone on loan, as he still has three years left on his current contract with Wolves. This would give him the opportunity to gain more experience while also benefiting Sunderland's goalkeeping department.
Johnstone made ten appearances for Wolves during the last season, demonstrating his ability to perform at a high level.
