Injuries can very possibly. While the main starting 11 is great and a good bunch of the bench is too, it doesn't take many injuries for the current Chelsea team to look fairly thin. Meanwhile a team like City got pretty much a competent replacement for each and every starting 11 and will probably not have as many matches to play, when they crash out of Europe. If you meant a single team... Ehm, probably some shit like Sunderland yeah.