But his club, Saturn of Russia, rejected the offer and now Karel Csonto does not think they will back with a renewed offer.
"About three days ago Celtic representatives contacted us and said that they would like to capture Jan Durica. I personally discussed the transfer with Celtic chief executive Peter Lawwell," Csonto told SITA.
"The Scottish side have offered Saturn a €4 million bid, which is not an adequate offer.
"The Russians have already turned it down. Personally, at present I don't see his move to Celtic too realistic."