Defender Joleon Lescott has been ruled out for up to five weeks with a hamstring problem and so will not face former club Everton at Eastlands in the Barclays Premier League.
The England international was injured in the warm-up at Fulham at the weekend and his replacement at left-back then, Javier Garrido, is expected to keep his place with first-choice Wayne Bridge sidelined after a hernia operation.
Striker Emmanuel Adebayor serves the final game of his four-match suspension.
City have yet to lose at Eastlands this season, winning nine and drawing four, but Mancini insists they cannot rely on their six remaining home matches to see them through to fourth place.
However, he believes 21 points from a possible 27 would get them into the Champions League next season.
"If we win seven games I think we go, but I think it will be difficult," he added.
"If we want to get fourth spot we must win always. It will be important that we win at home and away.
"In the last three games we have won in London twice, against Chelsea and Fulham, and drawn at Sunderland.
"It is important we have the same spirit away as we do at home."
Everton forward Victor Anichebe has returned to training ahead of the trip.
The Nigeria international was carried off during Saturday's defeat of Bolton after an apparent blow to the ribs but a scan has shown no damage.
On-loan Arsenal defender Philippe Senderos, whose time at the club has been blighted by injuries, is also close to returning after a medial ligament strain.
Manager David Moyes reports "one or two knocks and niggles" but otherwise long-term ankle injury victim Marouane Fellaini is the only major casualty.
With just eight games to go and five points to make up on seventh-placed Aston Villa, Moyes has played down the possibility of a return to continental competition.
Moyes said: "I think it is too big an ask to catch the teams above us.
"I think we would need to do really well and expect those teams to falter quite a bit.
"Those teams have got the points in the bag and we would need to do our talking on the pitch, but it is a big ask."
To maintain their interest Everton will need to transfer some of their home form to their away performances.
Saturday's 2-0 victory over Bolton was the club's seventh in succession at Goodison Park - their best run in the league for 20 years.
Moyes said: "We started slowly so we needed to go on a good run of home games.
"But the important thing is to try to win the next game.
"I think we have been playing well for a few months but there has also been the odd blip in there.
"We have got ourselves in a healthy position when you consider where we were in October-November.
"That is all credit to the players, they have worked really hard."
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