Mourinho insisted the friction between him and Arsene Wenger are in the past, unless the Arsenal manager contributed to the scheduling of the match.
Mourinho was critical of Wenger during his first spell as Chelsea boss - at one point calling the Frenchman a "voyeur" - but on his return to Stamford Bridge revealed any differences had been ironed out.
"We have no problems," said Mourinho, before smiling when he added: "Unless you tell me that he had an influence on this. If you tell me that..."
The fixture schedule means Chelsea, playing their fourth of five games in 15 days, will be without the players who featured in the thrilling 2-1 win over City.
Initially, following the draw, Mourinho suggested he would pick a youth team. The reality is the Chelsea boss will select a side similar to the one which won the previous round at Swindon.
That side included World Cup winner Juan Mata and is far from weak as the Blues go to the home of the Premier League leaders.
Chelsea discussed fielding a youth side, but opted against it. Mourinho added: "It's not the plan. We have to respect also our fans.
"We discussed that in the club. [But] we have to protect our players. We are going to try to do our job and we will do our job the best we can."