Carlo Ancelotti has turned down the chance to return to AC Milan, telling the club he needs rest.
Jose Mourinho insists Diego Costa is content at Chelsea in response to reports linking him with a return to Atletico Madrid.
The 26-year-old has shone for the Canaries in their rise to the top flight and has become a regular in Roy Hodgson's England squad.
However, Ruddy faces a substantial period out of action after being forced off with a thigh injury eight minutes from the end of Saturday's 1-1 draw with Everton.
A post on Norwich's official Twitter account said: "City can confirm 'keeper @Johnruddy86 has a thigh injury which is being assessed, but he could be out for approximately 3 months."
The club's confirmation followed a tweet from Ruddy himself, revealing he will go under the knife this weekend.
The goalkeeper, @Johnruddy26, said: ''Just to update everyone on my injury, unfortunately I have torn my thigh will be having surgery on saturday and out for up to 3 months, :(''
It is a huge blow for in-form Norwich, who are unbeaten in their six Premier League matches heading into tonight's match at Southampton, where Mark Bunn deputised for Ruddy.