With Champions League qualification to the next round still a possibility if Chelsea can get a point at Barcelona, a few players could be rested but then there's a top 4 race that looks like they're they're losing pace, its a tricky game for Chelsea.
Manchester City, on the other hand, has proven that they are in a league of their own, no other team comes close to them in the English game and the best Chelsea can get from the game is a low scoring defeat, considering the pressure on their manager and the players coupled with their leaky defence....it will be an entertaining game though.