Celtic are one of a clutch of clubs reported to be interested in Atletico Madrid's unsettled winger Martin Petrov.
The Bulgarian international joined Atletico last summer from Wolfsburg in an é¼8.5 million (£5 million) deal but has struggled to find top form.
He has played regularly, making 28 appearances this term, but has failed to have the impact expected of him, netting just one goal.
Indeed, the 27-year-old has cut a forlorn figure on occasion this term and has already received a warning from Atletico to scale down his protests to referees over what he sees as a lack of protection.
He has also struggled to adapt to life in Spain and still speaks very little of the language which his employers perceive as a major factor in his failure to settle.
Publicly Atletico are insisting they have taken no decision on the player's future, but several sources are claiming that Los Rojiblancos will offload Petrov should they recoup most of the money they paid for him last summer.
"We have still not decided about the subject (Petrov's future), but it is obvious he has great quality and is well-known throughout Europe," stated Atletico director of sport Toni Munoz.
A number of clubs are monitoring Petrov's situation, but the front-runners for his services are understood to be Celtic, Fiorentina and Galatasaray.
Having reclaimed the SPL title this year, Celtic boss Gordon Strachan is looking to strengthen his squad ahead of next season's UEFA Champions League campaign.
Petrov's Bulgarian international team-mate, and namesake, Stilian is already on the books at Parkhead, although he recently saw a transfer request turned down.
If he was to stay this summer he could play a major role in persuading the left-sided player to switch Spain for Scotland.
Petrov himself has refused to be drawn on his immediate future, stating: "I am only thinking from day to day."