Cardiff City midfielder Joe Ledley may be forced to undergo a hip operation before the end of the season.But the Wales international has been passed fit for third-placed Cardiff's trip to Middlesbrough on Sunday. [LNB]Ledley visited a specialist to assess his long-standing hip problem and scans reveal the 22-year-old will eventually require surgery to cure his problem. [LNB]A club spokesman said: "The club knows he will need an operation, possibly before the end of the season." [LNB]Ledley hobbled off in the 64th minute of Cardiff's 1-0 win over Preston North End on Saturday with a recurrence of the problem. [LNB]He was forced to miss Tuesday's superb 2-0 win at second-placed West Bromwich Albion which fired the Bluebirds to third in the Championship. [LNB]Cardiff's spokesman continued: "Joe had a scan on Monday on the injury he suffered on Saturday and that found he had done nothing to worsen the condition. [LNB]''He was looked at again on Tuesday and will be fit and available for Sunday."[LNB] Joe, if you put him on a scale of one to three and three being the worst, Joe's at stage one Cardiff City manager Dave Jones Ledley and striker Jay Bothroyd, who was suspended for the triumph at the Hawthorns, are set to be available for the visit to play-off rivals Middlesbrough on Sunday. [LNB]Ledley, who is the final year of his Bluebirds contract, is expected to be out for up to three months if he does have surgery on his troubled hip. [LNB]The Cardiff academy graduate has been linked with moves to the Premier League sides and Scottish giants Celtic and Rangers. [LNB]He was publically criticised by Bluebirds chairman Peter Ridsdale at a recent fans meeting when he said: "Joe Ledley is playing like he is somewhere else already." [LNB]Ledley, who displays this season have been below his usual standard, insists his hip injury is having a detrimental impact on his performances. [LNB]But boss Dave Jones told BBC Sport: "Joe, if you put him on a scale of one to three and three being the worst, Joe's at stage one. [LNB]"And Joe wouldn't play - or any other player at this football club - if they had an injury."