The Hoops are keen to bolster their defence and 21-year-old Troost-Ekong is in the frame to follow former Groningen star Virgil van Dijk to Glasgow.
Celtic are expected to let van Dijk leave for big money, while Belgian centre half Jason Denayer is set to return to parent club Manchester City.
But Troost-Ekong - a former Fulham and Tottenham Hotspur youth player with Netherlands Under-19 and Under-20 caps - has been earmarked as a potential replacement, having told Groningen bosses that he wants a return to the UK.
He has spent time on loan at Dordrecht, helping them secure promotion to the Eredivisie, and last year received an invitation to Nigeria’s Under-23 training camp after committing his international future to the Super Eagles.
Standing 6ft 3in, Troost-Ekong has made over 20 appearances for Dordrecht, where he is currently completing a second loan spell. He signed a four-year deal with Groningen in July 2013 after being released by Spurs.
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