Grandison has struggled with the troublesome complaint since January and it was hoped that surgery would not be required, but manager Graham Turner admitted earlier this month that it was looking increasingly likely the 22-year-old would have to go under the knife to correct the problem.
That has now been confirmed and Grandison will undergo his first operation on Tuesday, with a surgeon shaving off a spur of bone in each hip.
Speaking at the start of May, boss Turner said: "He could be out for quite some time. The fear is it could be up to six months which will be a severe blow to us because he's very much an integral part of what we had planned."
Versatile Grandison is one of six players to have been offered a new contract by the Shropshire club.