The increasingly ageing and injury-prone 'keeper had been looking for a move away from Alan Pardew's side after dropping down the pecking order to fourth choice shotstopper.
The injury had been holding the 33-year-old up in training and after a period of rest and recuperation it was decided that the best option was to have an operation.
Physio Jon Fearn made the decision to send the former Oxford man in for the op as he explained to readingfc.co.uk.
"Phil attempted to treat it conservatively through physiotherapy, and everything was fine until he did some light training on Wednesday. He was still in discomfort and the only way forward was to have key hole surgery.
"The operation went as planned so hopefully he should be back in training within a month."
Whitehead is still hoping to secure a move away from the club in order to gain regular first team football.