The Wigan manager takes his side back to the Blues, the club he played for between 1994 and 1998 but says he will not go easy on Manuel Pellegrini's teamWigan Athletic face Manchester City, but he has no intention of doing his old side a favour.
The German takes his side to the Etihad Stadium for a repeat of last season's FA Cup final - won 1-0 by Wigan - in a quarter-final tie in this year's edition in the famous competition.
Rosler enjoyed a four-year stint at City between 1994 and 1998 during his playing career, and has credited the City supporters with helping him through his cancer battle, after being diagnosed with the illness in 2003.
The 45-year-old is looking forward to returning, but insists there will be no room for sentiment as he attempts to orchestrate a route to the semi-finals for the Championship outfit.
"They [the City fans] helped me on my way to recovery," he said. "In 2003, I was just recovering from cancer and finished with my treatment.
"I went there to say thank you for the support I got from the club and from the supporters and it was a very emotional moment. Now, 11 years later, I'm here with a wonderful football club as a manager. So it is quite a story.
"The emotions will be there but I also know that I'm a very professional guy and I'll focus on the job in hand.
"I gave them a DVD from that game [the FA Cup final] and from the league game. There is opportunities for us, but not a lot. We have to make sure we make them count. You never know. We'll see what happens.
"We come in off the back of a very strong month and we want to keep the momentum going. Obviously, Manchester City come back off winning a cup, winning the first trophy this season, and I think that makes them hungry.
"That is not good news for us. [but) I think they know that our team can cause them problems, so I think they will take us seriously."