Christie sustained the problem during last weekend's 1-0 victory at Stevenage and duly missed Tuesday's Johnstone's Paint Trophy exit at the hands of Leyton Orient.
Sky Blues boss Steven Pressley is disappointed to lose the 21-year-old's services for the short-term but admits he is relieved scan results have not highlighted a more serious complaint.
"We got the results of the scan back this week and our physio has made a further assessment of the results. He is likely to be up to four weeks out," Pressley told the club's official website.
"On the face of it it is an absolute blow, but we did fear it could have been even worse than that. Although I am bitterly disappointed he will be out, I am delighted it isn't for an extended period of time."