The champions are set to be involved in a six horse race for the title, with Man City, Chelsea, Liverpool, Arsenal and Tottenham all with eyes on the Premier League title.
“I think Chelsea have been overlooked,” Fletcher said.
“Chelsea started the season on fire last year, but didn’t win the league, so we have to be careful. Chelsea are a top side with a lot of experience. They have a new manager and they have brought younger, fresher and exciting players in.
“Liverpool have signed players as well, so it’s a tough league to play in this season. Although the two Manchester clubs have started well, the other teams are going to be dangerous. With the quality of the teams in the league this year, I think it will be our biggest test so far to go and win the title.”