Ballack has missed the last four pre-season friendlies but the midfielder is set to return against Manchester United in the Community Shield at Wembley on Sunday.
Competition for places is fierce now that Ancelotti has chosen to field a diamond midfield and will become even more so if Pirlo comes to Stamford Bridge as expected.
Ballack, who played in a reserve friendly against Queens Park Rangers yesterday to improve his match fitness, said: "I feel good. It was important to come back quickly and good to have a game like this to come back.
"I have trained really well during the time I was injured on the bike and in the pool so I could keep up my fitness level. Now I'm happy to be back.
"It's always disappointing to be with the team [on pre-season trip to USA] and have to go back from such a nice tour but it was better for my recovery because there were a lot of flights over there.
"It was better for me to come back and recover over here.
"We are now using a completely new system with the diamond. We played it under Jose Mourinho a few times and some of the players know it.
"We have to adapt again because we have four in the middle with no wingers and a lot of the possession is different offensively and defensively, so we have to train a lot.
"We are doing double training sessions at the moment but I am used to doing that from Germany and it is normal in pre-season to work harder.
"There is a lot to do to prepare for the new season."