The Icelandic 18-year-old’s advisor Olafur Gardarsson admits there are several top European Clubs tracking Bjarnason.
Gardarsson is the also looks after Celtic kids Kjartan Finnbogason and Theodore Elmar Bjarnason, who’s contract is set to expire next summer.
Gardarsson said: “It is a dilemma. Birkir has to decide whether it would be better to join a top European club or stay at Viking to ensure he plays in the first team at this stage of his development.
“Kjartan and Theodore face the same problem. Celtic have been terrific to them and they are liked and looked after but need to make the step up soon.
“I understand the situation because Celtic have a strong squad but the boys need to consider their future.
“Birkir must also consider this situation before he makes any final decision.”