This is one of the things that will weaken Manchester City's performance against Real Madrid and Arsenal in the Premier League and in the UEFA Champions League, respectively. Kyle Walker is a good defender, and if he is not in the Manchester City squad that will face Real Madrid and Arsenal, the Manchester City defense will be vulnerable.
I totally agree with you because irrespective of how good Manchester City is and how they can easily cover up for a player who is injured but with the kind of player Kyle Walker is it will surely affect the performance of Manchester City because in terms of Manchester City defense Kyle Walker is there pillar and also no matter how strong a club is if there defense line is not good all there efforts will go to waste, although Kyle Walker injury is not that bad so he will surely play all there upcoming matches, so that's to say that Manchester City will be using all there full force on there upcoming matches.