Ashley and his cash would be welcome at Ibrox despite his controversial reign on Tyneside.
Green said: "I don't think Mike needs to throw money into the club.
"That's not the model that is sustainable for any football club.
"What Mike will do, subject to all the agreements, is bring the might of Sports Direct and that in my mind will bring in £5-10million a year from merchandise.
"That is far, far more worthwhile than Mike signing a cheque."