Ligue 1 side Saint-Etienne are currently leading the race to sign the 2-time Bundesliga player, but Celtic would only have to pay £2.65million to hijack the French side move for the well-experienced centre-back.
Subotic has been out of favour at Dortmund of recent, and could be on the lookout for a new side to ply his trade with after a 10-year association with the Bundesliga giants.
The 29-year-old Serbia defender has featured in just five matches for the BvB this season, and the arrival of Manuel Akanji from FC Basel further makes him more deem surplus to requirement under Peter Stöger.
With European competitions triumph one of Brendan Rodger’s side weaknesses, signing a player who is well experience could help improve things at heart of defence at Celtic.
Despite just signing Marvin Compper, the Dortmund’s Champions League finalist can help a bring depth to a a rearguard that saw both Dedryck Boyata and Jozo Simunovic spend time on the injury sidelines earlier on in the season.
Elsewhere, Celtic are one of a number of clubs said to being interested in signing Red Star Belgrade forward Luka Adzic, according to his agent.
The 19-year-old has been severally touted as a target for Premier League club Leicester City and Championship side Sunderland, but the Bhoys have also seemingly entered the race to sign him.
His agent, Radojica Bozovic was quoted as saying:
“I know that there is an interest from Celtic, but also some other clubs for Luka, but there was no concrete offer.”