Kolarov has played a lot of minutes under Pellegrini. Maybe like with Dzeko he is willing to give him a chance. Whatever people say about his defending, his offensive contributions should not be overlooked. Always provides the width, and almost always threatens with his crosses/shots.
From the games I have seen it looks like he is more fired up than last season. Not surprising maybe, he wants to try and impress the new manager, much like Dzeko I guess. Hopefully Pellegrini instills some urgency into his defending - and hopefully he never makes a back pass like THAT one a couple of weeks ago.