Speaking to BBC Sport ahead of the new season, England defender Walker has admitted that City must be careful of Liverpool and the other sides that will be looking to secure the Premier League title in 2018/19.
The window closes on Thursday Aug. 9, three weeks sooner than normal, with the Premier League season starting on Saturday.
Premier League chief executive Richard Scudamore hopes defending champions Manchester City face a stiffer challenge in the coming season.More news: NASA mission to get closer to sun than ever before
Manchester City were the dominant force in English football last term as they racked up a record points tally of 100 on their way to the title.
Another specialist holding midfield option alongside Fernandinho was also a priority but City's pursuit of Jorginho ended with the Italy global moving to Chelsea from Napoli. The Anfield friendly saw goals from Roberto Firmino, Georginio Wijnaldum and Daniel Sturridge, but new signing Fabinho missed a penalty.
But he sounded a different tone at Sky Sports' Premier League launch event on Tuesday when discussing the options within his squad who can operate at the base of the midfield.More news: James Gunn's Script Will Be Used For Guardians Of The Galaxy 3
"As with all these things, it's only when it comes upon people - but again it wasn't a unanimous decision to do it, so there's bound to be some dissent still around".
With this year's deadline taking place much earlier than usual - it's normally the end of August - the Premier League has revealed there will be a review. It is going to be challenging, particularly for the promoted clubs, who effectively have two-and-a-half weeks less.
I don't think we are going to sign more this season.More news: China defends Iran business ties after Trump threat
However, they can still sell players to clubs overseas because English clubs have brought their transfer deadline forward, but it remains at the end of August across Europe. "It's up to us to achieve them dreams".