The former midfielder says the players they may want to buy will already be at top clubs.
Spurs are in a fine run of form at present, with them currently unbeaten since the opening day loss to Manchester United.
They continued their fine spell on Sunday, with a 4-1 win over rivals West Ham United at White Hart Lane taking them to within two points of the top four.
With that race, and the title race both wide open, there are suggestions that Mauricio Pochettino’s side could be title challengers this season.
They may look to boost those hopes with signings in January, but Redknapp says the players they would want to acquire would be hard to get hold of.
“You never know with Tottenham whether they will try and buy somebody in January,” he told TalkSport.
“But even then is it difficult to buy the players you want. If you are looking to maybe go and win the league or break into the top four, a lot of the players you want to acquire are already at good clubs.”
If there is one area of the team that Spurs need to strengthen, it is certainly in the striking department.
They are heavily reliant on Harry Kane to score the goals for the side, with their failure to secure another striker, notably Saido Berahino, in the summer widely criticised.
However, securing a top class centre forward in January would be near on impossible, with sides often reluctant to let their best talents leave mid way through a campaign.
Spurs then, may have to rely on what they have to get them into the top four or beyond, with January likely to prove a frustrating period.