According to the Daily Mail, Celtic are lining up a January move for Eibar defender Aleksandar Pantic, who is currently on loan from Villarreal.
Pantic, 23, played for Serbia's two biggest club, Partizan and Red Star Belgrade, before moving on to Spanish side Villarreal in 2013.
The centre back made just 13 appearances for Villarreal before being farmed out on loan to Cordoba last season, and now Eibar this term, with seemingly no future at El Madrigal.
An ex-Serbian Under-21 international, Pantic has become a solid defender in Spain, but he could end up moving over to Scotland if Celtic get their way.
The Daily Mail report that Celtic boss Ronny Deila was in Spain to watch Eibar take on Real Betis on Sunday, and whilst he was scouting strikers Borja Baston and Sergi Enrich, it's believed he was also checking out Pantic in a desperate attempt to solve his defensive problems.
Summer signings Dedryck Boyata and Jozo Simunovic haven't been able to replicate the partnership of their predecessors Jason Denayer and Virgil van Dijk, and Celtic fans are keen to see Deila bring in a new centre back in the near future.
With Pantic, his Villarreal contract expires at the end of the season, meaning Celtic could offer him a contract this month in order to join for free in the summer, rather than secure a deal now, which may be what Celtic fans would prefer to see.