The 22-year-old has played an average of 43 games a season since he joined Manchester United from Everton.
Ferguson said: “They all know it has to happen.
“I understand that some players want to play every week — Eric Cantona was like that — but it cannot happen.
“For too long I’ve been operating with two strikers, which is ridiculous for a club of this size.
“To achieve what we want to achieve we need four strikers of the quality we had in 1999 with Dwight Yorke, Andy Cole, Teddy Sheringham and Ole Solskjaer.
“Whoever plays will not be down to performance.
“It will just be about keeping them fresh.
“For example, in 1999 Yorke and Cole had a great partnership so they were always in front.
“Yet it would be Solskjaer and Sheringham scoring the goals at the right time because I could freshen things up.”
He continued: “Maybe Wayne has not been getting a lot of chances at the moment.”
He added on the arrival of Dimitar Berbatov from Tottenham: “Berbatov will bring good composure, experience and presence. There is no doubt in my mind he will improve us. He is someone who has good decision- making and timing which will improve things for us.”
