Manchester City: Biggest Concerns in the Early Stages of New Season

Despite mostly positive results so far this season, Manchester City have pretty big concerns early on.

Roberto Mancini has shown his willingness to vary things tactically, but that hasn't worked out as well as planned.

One or two key players are missing due to injury, while others who are available are suffering from a dip in form.

City has a long road ahead in terms of defending their Premier League title. However, with the squad at hand, they should be challenging for the top spot all the way.

Things will be more difficult in Europe, but a side with such quality players will still be expected to reach the knockout rounds.

Here are some of the biggest concerns for Manchester City in the early stages of the season.

For whatever reason—individual mistakes, tactical decisions or the formation chosen—this Manchester City defense isn't even close to replicating the kind of form we saw in 2011-12.

City has yet to keep a clean sheet in any game this season, including the Community Shield.

An almost impenetrable defense, led by Vincent Kompany and Joe Hart, carried this team to a Premier League title last season.

Things will not get easier for the club when they face Arsenal this weekend. The coaching staff and players must rectify the situation.

In two of Manchester City's biggest games of the season so far—at Liverpool and at Real Madrid—Roberto Mancini made some questionable decisions.

Against Liverpool, he didn't appear to make any glaring mistakes, except for his decision not to change from the 3-5-2 formation which clearly wasn't working.

His substitutions didn't have a major effect on the game. That is, unless you count substitute Jack Rodwell handling the ball and conceding a free kick, which Liverpool striker Luis Suarez was able to score from.

Ultimately, Mancini was lucky to escape with a draw.

On the other hand, against Real Madrid, the Italian made an obvious tactical mistake.

Given the opposition, starting the game with a defensive mindset wasn't the worst decision in the world. However, unlike the game against Liverpool, Mancini was unable to get away with the one major decision that changed the matchup.

That decision was analyzed at Zonal Marking.

Rather than reverting back to a 4-2-3-1 formation after gaining the lead for a second time, Mancini handed the whole left side of the pitch to one of the players in the world and attack-minded full-back Marcelo.

In this game, with a major amount of luck, two of Mancini's substitutions worked out well.

His third was disastrous.

If the Citizens boss continues to make poor decisions against Arsenal this weekend, he and his team could be in real trouble.

Home advantage will help, but the Gunners are a confident team at the moment and have shown their effectiveness offensively thus far.

It's still very early in the season, but City must be concerned with the form of David Silva. Even with Samir Nasri in the squad, the Spaniard is the club's key playmaker.

Silva is probably still recuperating from his time at Euro 2012 and the distraction over his new contract.

With those contract issues recently resolved, hopefully Silva can now focus fully on his football.

The good thing is that Nasri, Carlos Tevez and others have been productive so far this season, and the squad is yet to see Sergio Aguero play a full 90 minutes.

With that being said, with his vision and passing skills, Silva led the league in assists last season for a reason.

He will go up against his Spanish teammate Santi Cazorla on Sunday, and City will need him to control the midfield to get the victory.