The Perth side are resigned to losing their talismanic number one, who has turned down the offer to his extend his contract which expires in the summer.
Asked about reports that Aberdeen had informed Saints that they would be speaking to the recent Scotland call-up about signing a pre-contract, Davidson said: "A lot of clubs have been interested in Zander, not just Aberdeen.
"He has probably been our best player so far this season.
"He will be able to have a pick of clubs, hopefully there will be clubs in England as well, interested.
"It is a big chance for him. He has been here for 10 years now. It is a big, big decision for him to make.
"If he keeps performing the way he does, he will have a lot more choices than just Aberdeen."