Glenn Hoddle believes that Manchester City are playing well below par this season due to the form of Yaya Toure.
Manuel Pellegrini's side struggled against the 10 men of Bayern Munich in midweek without the suspended midfielder as they needed a hat-trick from Sergio Aguero to keep their Champions League hopes alive.
Hoddle feels that, even with the Ivorian in midfield this season, City have looked far from convincing and believes this displays how important Toure's form is to the club.
The former England manager told the Daily Mail: "At the start of the season two teams dominated most predictions for the Premier League. Yet one of them has probably surpassed expectations and is shaping up to be one of the great Premier League sides, the other is well below par.
"I am, of course, referring to Chelsea and Manchester City. When you analyse where it is going wrong for City, there are some obvious areas. Yaya Toure clearly isn't the player he was last season, for whatever reason. We can't know for sure but it might have been the loss of his brother, who tragically died in the summer.
"It certainly seems to have gone downhill ever since there was that silly row about his birthday after the summer trip to Abu Dhabi. Only now are some people realising quite how important he was to the whole team."
City face Southampton at St Mary's Stadium in the Premier League on Saturday, nine points adrift of leaders Chelsea.