OK, let me try and make this easier for some of you....
The City game is to have attacking full backs and to pack our players into the width of the pitch between the 18 yard box. It is not a new tactic, and is what made Zaba famous,many Clichy deemed a liability (because he never gets a cross in and loves to check back inside and slow/stop the play).
Sterling was bought to add speed and backtracking to our left flank, because we need to have some speed AND COVER for our marauding full backs. His forte is taking in players and pulling them outside while he heads inside for a shot on his right foot...because his left is for standing on. It was even mentioned in the commentary today by Danny Mills when Kyle Walker got jinked. Sterling does NOT want to go outside and whip a ball in....cue Aleks Kolarov!
Kolarov is an option to get the ball into the danger area for our striker and attacking midfielders. I think you can count the number of times Sterling has done that on one hand....not because he is shit, but because that is not his game, just like Navas (which is another story!).
Sterling clearly has ability, but he has to use that ability to produce results in the City scheme. He can do it, because he has already done it. Today was a bad day at the office for him. The defender was up his arse the whole game and he rarely had a chance to run at anyone. However, as we saw when Lloris made a magnificent save down to his right, Sterling definitely has the ability to cut inside, make half a yard for himself and grab a hatful for goals over time, but he just looks short of confidence.
Today, I'd have taken him off and put Barker on for the last 15-20 minutes. As it was, Pelle chose to give Roberts another run out and put Sterling in the middle, giving Aguero a bit of a rest for midweek.