Returning manager Jose Mourinho has already recruited Andre Schurrle, Marco van Ginkel and Mark Schwarzer so far this summer, and reports claim that the Blues are keen on bringing Manchester United striker Wayne Rooney to Stamford Bridge.
"We all know about Wayne and how good a player he is. He's world class. I'm sure he'll sort out what he's doing in the near future," Cahill told Sky Sports News.
"Transfer windows is just players coming and going. Sometimes it's better when the window shuts and it settles down and you know what squad you've got.
"You don't know whether things are true or not. You've just got to get on with our job and get ourselves fit and get prepared for the start of the season."
Chelsea are currently on tour in Asia.