Ballack missed several vital games including the Champions League semi-final second leg against Liverpool.
The lost their Premiership title at the weekend.
Ballack went off to Germany to to have the operation but on Wednesday Jose Mourinho refused to eleborate on the issue.
Anyhow in there infinite wisdom and in the blind hope to put a seal on the issue, Chelsea have said: "In answer to recent speculation regarding Michael Ballack's injury, nobody's future at Chelsea Football Club was ever in doubt following his operation. There is also no doubt that Michael has put Chelsea FC's interests first.
On speculation regarding the diagnosis of the injury, this has never been an issue. There was a debate on when an operation should take place, and there was a final agreement on that surgery taking place.
Chelsea and all its players have full confidence in our medical team headed by Bryan English and his professional reputation.
All parties involved have discussed these issues and endorsed this statement. There will be no further comment from anyone.
So there you have it, Bryan English's name has been mentioned in the statement - what was the issue with him and his professional reputation?
Is someone suggesting anything different?
Ballack is in training and it's suggested by Jose he has 0% chance of playing in the FA Cup final on Saturday week.
With Ricardo Carvalho also out and Andriy Shevchenko also injured, Chelsea are getting close to the bare bones of top-class players to take on Manchester United.
Frank Lampard will probably be rested for part of Sunday's match against Everton.
Didier Drogba, likewise is expected to be on the bench at best.
Ashley Cole is close to returning but the form of wayne Bridge might tip Jose hand in giving the left-back Cup Final berth to Bridge.