The troubled ex-England international, currently battling alcoholism after a stint in rehab in the USA, indicated that 'Gers can get back to former glories if McCoist is given permission to purchase the players he wants once the transfer embargo is lifted in September.
"Once Coisty starts investing in the players he wants then you can judge him properly," he told SunSport.
"That will be him as the real Rangers manager, when he has an open wallet to play with.
"Right now you are seeing 50 per cent of the coach I believe he can become.
"Give the man a chance because he is keeping the club afloat right now. I am glad Charles Green has had the common sense to realise what Ally has been left with and kept him."