After steamrollering their way through the first half of the domestic campaign, City have suddenly encountered their first major hurdle.
One win in five games includes an FA Cup exit to Manchester United last week and a home defeat in their Carling Cup semi-final first leg against Liverpool.
The consolation is that neither of those results has had any effect on City's league title hopes, and victory at the DW Stadium will put them three points clear of United once more.
But, with injuries, suspensions and international calls biting deep into their squad, City must roll up their sleeves and counter anything rock-bottom Wigan hit them with.
"This is the time when people will really be watching us, to see how we respond to this sticky patch," said England midfielder Barry.
"If it means going there, not playing great football and battling to get a victory, we might have to do that.
"You can't dominate the whole league playing fantastic football and winning every game easily. Sometimes you have to battle and scrape a result in the last minute.
"Wigan is set up for that sort of game. Everyone in the dressing room has to roll up their sleeves and be ready to do it."
With Kompany serving the second game of his four-match ban and Yaya Toure away at the African Nations Cup, Montenegro defender Stefan Savic is set to continue in central defence even though the 21-year-old looked ill at ease as he squared up to Andy Carroll last week.
Mancini could opt to play stand-in skipper Micah Richards alongside Joleon Lescott, with Pablo Zabaleta at right-back.
However, it is a measure of how depleted his squad is at present that Mancini has even put Nedum Onuoha's proposed move away from the Etihad Stadium on hold.
In fact, Mancini believes no side other than Barcelona could cope with the problems he is encountering.
"Maybe Barcelona could. Manchester City no," he said.
"In four or five years, Manchester City probably yes. But not now.
"When I said one month ago that December and January would be the crucial months it was because I know football.
"Every year in every squad you have one difficult moment. At the moment we are not strong and we have lost important players, so it is difficult."