But despite being operated on the Palace boss remains keen to embark on his summer recruitment drive having already discussed a number of potential targets.
Eagles assistant boss Mick Jones told the South London Press: "Neil's operation went well and he was in good spirits when I caught up with him shortly after the surgery.
"There was actually a little bit more work needed to be done then was initially expected.
"He is not letting the grass grow under his feet and is working on getting new players in. There have already been meeting between the manager, myself and Curley [Keith Curle] about potential targets.
"Neil has spoken to one player already and without being too optimistic the talks went well. The lad seemed to be keen to come to Palace - I don't know whether that is the reputation of Neil or that he feels success is just around the corner here."