The 24-year-old is currently with Belgian side Standard Liege, but has made just one appearance this season.
On his arrival at Glasgow Airport on Thursday, Gershon told STV: "I am very happy to be here. I am very excited to have the opportunity to play for Celtic. I just hope that everything will be done tomorrow and then I can speak more."
Gershon admitted he had not yet discussed the possible move with Celtic midfielder and fellow Israeli Beram Kayal.
He said: "I haven't spoken to him yet. He is a good friend of mine but everything was very quick so I didn't find the time to speak to him.
"But in the past he has told me only good things about Celtic."
Gershon's agent Dudu Dahan interrupted to add: "There is nothing to talk about. If a club like Celtic calls you then you should go on the plane and that is what we did."
If Gershon signs, he could be added to the club's Champions League squad for their last-16 tie with Juventus.
Neil Lennon is permitted to replace up to three players in his 25-man list for the tournament.