Reports over the last few weeks have suggested that Ferguson is keen to sign Borussia Dortmund striker Robert Lewandowski as a direct replacement for the England international.
However, when discussing the strength of his current squad at Old Trafford, Ferguson insisted that Rooney is now coming into his "peak" years.
"David De Gea, Rafael [da Silva], Phil Jones, Chris Smalling, Alex Buttner, Nick Powell, Tom Cleverley and Danny Welbeck. Shinji Kagawa and Chicharito (Javier Hernandez) are 24. Jonny Evans is 25 and Wayne Rooney is hitting his peak at 27," Ferguson told Inside United.
"Older players like Ryan Giggs, Paul Scholes and Rio Ferdinand may be coming towards the end of their careers, but these younger players are the foundation for the next five or six years, irrespective of the players breaking through, like Adnan Januzaj, the Belgian boy, who's really looking very good."
Rooney has been strongly linked with Paris Saint-Germain.