The 21-year-old, who joined the Foxes from Dinamo Zagreb during the summer for a reported fee of £13 million, has been touted for a loan move as Brendan Rodgers looks to bolster his rearguard.
Speaking after the 3-0 win over Suduva, the Celtic manager said: “Hopefully we can complete it.”
The Hoops are also closing in on a deal for former Kilmarnock midfielder Youssouf Mulumbu.
The 31-year-old former West Brom midfielder, who left Kilmarnock in May, was at Celtic Park earlier on Thursday.
“We’ve been on the lookout for an aggressive number eight,” said Rodgers. “Hopefully he gets through a medical this evening.
“He was exceptional for Kilmarnock. He fits the profile and has the experience. It’s a really good move for us.”