Charles Green has accused players who have refused to transfer to his newco Rangers of "opportunism".
So far, Steven Davis, Allan McGregor, Kyle Lafferty, Jamie Ness, Steven Naismith, Steven Whittaker, Sone Aluko and Rhys McCabe have confirmed objections to transferring their contracts to Green's Sevco company.
The former Sheffield United chief executive's consortium completed the purchase of the business and assets of Rangers for £5.5million when the club was consigned to liquidation.
The squad are due to report back to Murray Park for the start of pre-season training tomorrow but only Lee McCulloch and Lee Wallace have indicated they plan to commit to the new regime, although Dorin Goian could follow suit.
When quizzed about the eight who have refused to transfer their contracts under TUPE employment regulations, Green told Sky Sports News: "I'm very, very disappointed of course.
"Particularly so late in the proceedings.
"It is clear in the regulations, if someone has an objection they have to notify within 24 hours, this is nearly two weeks.
"I think this is just opportunism. We will definitely challenge it, yes."
Asked whether he expects more players to try to quit the Ibrox side, Green added: "I've learnt not to expect the expected at Rangers."
Green's application to join the Scottish Premier League looks doomed and he could be forced to relaunch the club in the Irn-Bru Third Division.
A formal vote will take place on July 4 but six SPL clubs have already gone public with plans to reject the Rangers bid, with an 8-4 majority required.
Midfielder Davis claimed he had to put his career first after turning down a move to the newco Rangers.
The Northern Ireland international, who joined Rangers in 2008, captained the club through four months of administration.
In a statement published in the Daily Record, Davis said: "Only those who know me will know how much Rangers mean to me.
"I signed a new contract last year, giving my best years to the club in the knowledge we'd be challenging for leagues and cups and in Europe year after year. That's the reason I came to Rangers.
"My young family love life in Scotland but after all that's gone on since administration in February, there came a point when I needed to make a decision based on what was best for my short career.
"I am 27 and need to be playing at the highest possible level."
John Fleck is reported to be on the verge of leaving amid similar frustration and others could follow.
Romanian defender Goian could stay, but that situation may change if a plan to put Rangers in the First Division fails.
His agent, Florin Manea, told the Scottish Daily Mail: "The people at Rangers have assured us that the contract will remain the same.
"If the club is doing this for us, then Dorin doesn't have a problem staying at Rangers - even if they go to the second league."
However, pressure is intensifying on Green with fans set to protest outside Ibrox tonight over a lack of clarity surrounding his investors and plans.
Former Rangers player John Brown has also declined to transfer his contract as a scout over to the newco and he plans to lead a fans' buyout of the Sevco group.