Kevin McNaughton is out of contract in the summer

The 23-year-old defender is out of contract in June after turning down repeated offers of a new deal.

"It's disappointing but we did all we could to try to persuade him to stay," Calderwood told the Evening Express.

"Aberdeen can no longer compete with clubs in the English second and third divisions and many abroad when it comes to wages."

The versatile defender has been linked with a move to Dundee United but Calderwood dismissed that notion.

"He chose not to tell me where he is going, although he just laughed and said that wasn't happening when I mentioned the link with United," added Calderwood.

"For the sake of his career, I hope it is to a club that will be successful and help to bring him on.

"Kevin will stay in my plans for the rest of the season though.

"I've asked him to do his bit to ensure he leaves on the high by helping us finish fourth and maybe qualify for Europe.

"I've also started work on getting his replacement. I had already laid down contingency plans for this happening."