An exploratory operation on Thursday evening revealed cartilage damage and confirmed the 28-year-old’s and Blues boss Lee Clark’s worst fears.
Murphy, described as ‘the best left-back in the division’ by Clark, was substituted in the 85th minute of last Saturday’s fixture at home to Hull City and had made 14 starts this season.
The ex-Middlesbrough and Hibernian defender will now work hard on his rehabilitation with a view to returning for pre-season training ahead of the 2013/14 campaign.
Everyone at Blues sends their best wishes to the club favourite.