Naismith has been the subject of repeated offers from Rangers

The Ibrox club have had four bids for the 20-year-old knocked back and insist they will no longer pursue the matter.

"Steven's reached the end of his tether and needs to leave," Andrew McCormick told the Daily Record.

"Steven's father has expressed concern over his son's health because his head is in such a mess he can't sleep."

Rangers were offering a fee in the region of �1.5m for last season's SPFA Young Player of the Year in the Premier League.

And McCormick was critical of Rugby Park chairman Michael Johnston's handling of negotiations.

"Steven is disillusioned with the treatment he's received from a chairman whose handling of this saga has been quite incredible," he added.

"Johnston seems to spend more time communicating with fans on websites than he does telling Steven what is going on.

"The player and chairman have no working relationship whatsoever.

"Steven is being denied an opportunity to better himself and increase his earnings 10-fold. I defy anybody not to become frustrated in those circumstances.

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"It's like having a winning lottery ticket in your hand but Kilmarnock's chairman wants to rip it up and deny him the chance to cash it in.

"It's impacting hard on Steven and his family. They can all see his pain and it's distressing for everyone."

Naismith has three years of his contract to run and Kilmarnock want to get the best deal possible for their prize asset.

Last week, Killie boss Jim Jefferies indicated that Rangers were closing in on a deal.

And McCormick is of the opinion that the manager has also been let down by the prevaricating of his chairman.

"I also believe Jim Jefferies - who has been terrific with Steven throughout this whole episode - has questions he needs answered," continued the agent.

"It is my understanding that Jim has asked how the club can afford to knock back �1.5million when they've done nothing but cut costs since he's been there.

"Jim has been working on a shoestring and has done a magnificent job.

"But I think he's frustrated a guaranteed sum of money, one which might change his financial constraints, hasn't been accepted."