Toure, the champions' midfield driving force, might not be seen again in a City shirt for seven weeks as he prepares to leave for international duty at the African Nations Cup.
The 29-year-old Ivory Coast star missed eight games during last year's tournament, a period which saw City knocked out of both domestic cup competitions and lose an important Premier League game at Everton.
City recovered to win the title, but Zabaleta is anxious to ensure Toure's absence, along with that of his brother Kolo and back-up striker Abdul Razak, is not keenly felt this time.
The Argentina international said: "It's going to be a very tough time for us because we're going to lose Kolo, Yaya and Abdul, three important players.
"Yaya has been a regular player for a long time. We know how important Yaya is to the team but there are other players who can do the same job.
"Everybody is important for the team and we need to keep working hard.
"Last season, January and February was when we dropped points and we need to try to make sure that doesn't happen again."
City had hoped the players would at least be available for Saturday's FA Cup third-round tie against Watford - which is still more than two weeks before Ivory Coast's first fixture in South Africa - but any requests seem unlikely to be granted.
First-team coach David Platt said: "They are meeting on Saturday to travel. As far as I know there is no difference in that.
"Yaya, Kolo and Abdul, I don't think will be available at the weekend unless something changes - but I doubt it."
Striker Sergio Aguero has also been ruled out of Saturday's game after suffering a hamstring injury in the New Year's Day win over Stoke. City are still waiting to learn the extent of the damage but he is also doubtful for the following week's trip to Arsenal.
City captain Vincent Kompany also believes the reigning champions will cope with Toure's absence.
"Yaya has played every game; that shows you how important he is for the team but that is something we will have to deal with," he said. "It is like having an injury, it happens. We believe we have enough players to step up and make the difference.
"When you look at the strikers we have, not scoring goals should never be a problem in your season. We are back on target and defending well. When you start a new year, it allows you to start a clean sheet and forget what has gone before. We have done it in every way possible against Stoke - a clean sheet at the back and three goals."
Kompany also believes his team's success in overturning an eight-point deficit in six games to win the league proves their ability to overhaul United again.
"A couple of years ago, if we had fallen seven points behind, we would all have said to ourselves that it would be very difficult," Kompany said. "But now we have done it, nobody panics.
"Everything is still possible. We have proved what we can do and everybody is very calm. That's the advantage you get when you win it once.
"The reason we are not closer to United is not that we have been playing badly. We have only lost two games, which is not a bad record at this stage of the season, but United are doing extremely well. If they continue to play like they have been doing, it will be difficult, but we are perfectly capable of having a long, long winning streak that will bring us very close. It is a good challenge.
"It is a big challenge, but that doesn't make it any less interesting. When you have won the title, you aim for another one.
"That is not just the ambition for 2013, but for the future of the club."