Kevin De Bruyne is one of the most valuable players for Manchester City without doubt. His absence due to injury is really unlucky for them as well. However I don't think this would affect them deeply anyway. Because they are still one of the strongest teams in Europe now. They are full of world stars playing in coherence together.

There has been some drop in their form recently but it is no problem at all. I remember Manchester City having way worse times in one season and they were way behind the leader. But they still made an unforgettable comeback and won the title by a serious point gap.