The 22-year-old is attracting plenty of interest from right across Europe.
Ronny Deila has included the 22-year-old on a list of potential January targets, and the Daily Record claims that a £2.5m move was being lined up for next month. But while Dinamo Zagreb are ready to pull the plug on a move due to their unwillingness to meet the asking price, Olympiacos and Carpi also remain interested in a potential move.
With four other sides reportedly serious about a deal, Celtic face a possible bidding war should they want to complete a move. However, the Record states that Ronny Deila's men are likely to pull out of the equation should an auction between the interested clubs ensue.
Although the Bhoys may be wary that the asking price is set to soar should several cement their interest with a January bid, Mocinic is a promising talent that could become an integral member of the team for years to come, should he move to Parkhead.
He made his international debut for Croatia last month, which suggests that he may be in contention for a spot in the European Championship squad next summer.
Should he be selected, he may find that his value rises rapidly if he impresses in France, leaving Celtic completely priced out of the market, and wishing they had made their move in January.