The next few weeks could prove to be defining ones for Manchester City this season.
There's also the final Champions League group match away at Bayern Munich, a game that could still see City top Group D.
That game in Munich, though, requires City to better the 3-1 win the Germans managed in Manchester earlier in the group if it is to be of any benefit to the Blues, which is why the news of Arjen Robben's injury won't be too much of a fillip for them.
City manager Manuel Pellegrini would be well advised to concentrate on the club's tricky league games, rather than play a full-strength side in Munich.
The Dutch winger, who tore City apart in the first match between the two sides in October, is out for six weeks with a knee injury (via BBC Sport). The 29-year-old has been in fine form so far this season and would have been a danger man if selected to play against City.
Robben said: "Of course, I am very disappointed. I was in good form and I was really looking forward to every game with the team."
Top spot in Group D will bring huge benefits for whoever takes it. Avoiding the other sides who win their group offers a much easier route to the last eight, but City need to be pragmatic and accept that it's unlikely they will usurp Bayern.
Even without Robben, Bayern still have a fantastic squad of players to choose from and City will struggle to get the result they need.
The Arsenal match, which is fast becoming one of the most important matches at the Etihad in many months, gives City a real opportunity to close the gap on the league leaders, so resting players and taking no chances in the Bayern match—which is just four days before—is imperative.
Arsenal are a side many weren't prepared to accept as title challengers when their good run of form first began, but every side in the division must now accept they are potential title winners. Their front-six are functioning beautifully and Per Mertesacker and Laurent Koscielny are in superb form at the back.
They currently have a six-point advantage, meaning the game at the Etihad is of huge importance.
Robben or no Robben, the Bayern match should be one in which City rotate.
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.