A hernia operation has kept Lampard out since the end of August, while Terry sat out Sunday's 4-0 win over Blackpool due to a rib injury.
Chelsea's Carling Cup third round tie with Newcastle on Wednesay will come too soon for the influential pair, but Ancelotti expects them to return for the Blues' toughest game of the season so far.
"Frank is training, he is not 100 per cent yet," Ancelotti said. "He will be able to play against Manchester City. Terry had a problem with his ribs and was not able to play, but he should be okay in two or three days."
Ancelotti admitted after the victory over Blackpool that the visit to Eastlands will likely be his side's trickiest encounter of 2010-11, but he stressed that he believes in his squad's ability.
"It could be we have had an easy start," Ancelotti said. "Every game could be easy after and if you've not played well, you've had a difficult game.
"We didn't play against the top teams but we are playing very well and that is the most important thing. Now we have to maintain the same level of play against the top teams and I think we are capable of doing this.
"I thought for us it was important to show confidence in our play. We know the next game will be difficult and if we can show the same level of football against a team like Manchester City it will be an important test."