Florin Manea, the defender's agent, revealed both parties are still determined to strike a deal, with the player citing Champions League football as a big incentive for the move.
"We have had some very positive talks with Mr Lawwell and I am confident a deal can be done," said Manea. "Not only is he a managing director, but he is also a Celtic fan and he wants the best deal for his club and we understand that.
"Gabi wants to play for Celtic, in front of those great fans in that great stadium. Also, the idea of Champions League football is very attractive. He played in the tournament for Galatasaray against Juventus when he was 19 and he wants more of that.