The injury to Fernandinho, which according to Mark Ogden of The Telegraph isn't as bad as first feared, left a gaping hole in the middle of the park, allowing Nemanja Matic to take control as Chelsea eased to victory.
It's a problem that has been on the horizon for a while. Yaya Toure and Fernandinho, who have been exceptional in tandem, have little in the way of competition and, as a result, have played too many games. Fernandinho has picked up a thigh problem, and Toure could suffer similar muscle injuries given his heavy workload.
It's this pressure on City's first-choice midfield pair that saw the club attempt to sign Fernando from Porto in January, a deal that collapsed at the last minute. It may be revived in the summer after an informal agreement between City and the player was reached (according to Ian Herbert of The Independent). For now, though, they look short of options.
It was left to Martin Demichelis to try and fill the void left by Fernandinho in the Chelsea match, but he struggled with the intensity of the midfield battle. Demichelis has brought certain qualities to the centre-back position, such as his reading of the game and aerial ability, but his chronic lack of pace made his inclusion in the midfield seem rather misguided.
Chelsea completely dominated that area of the pitch, and Demichelis wasn't helped by Toure, who put in an understandably tired, laboured display.
James Milner can operate in that role and would surely have started but for the fact that he was coming back from a groin strain and had only trained for one day. Javi Garcia, who has been City's first reserve in that position for much of the season, was also out and has failed to fully convince since his move from Benfica in 2012, anyway.
Jack Rodwell was on the bench, but it is becoming increasingly obvious he doesn't have the manager's trust. A series of injuries have stagnated his progress, but even when fit he's often overlooked by Manuel Pellegrini.
It's clear, then, that City would have benefited from tying up the Fernando deal last week, but they, quite rightly, refused to be held to ransom. They had a value they felt reflected both the player's ability and his contract situation—Porto wanted more.
It's good to see the club no longer paying over the odds for players, but it does leave them somewhat short in midfield for the remainder of the season. Where City can take heart, though, is in the fact that no Premier League club has a perfectly balanced squad and, if anything, theirs is the strongest.
The title race is likely to go down to the wire, and City will have to be prepared to fight for it without the comfort of midfield depth.
Rob Pollard is Bleacher Report's lead Manchester City correspondent and will be following the club from a Manchester base throughout the 2013-14 season. Follow him on Twitter here @TypicalCity.