United are being linked with a £6 million bid for England U21 international Thomas Ince.
"If Paul Scholes was retiring and they needed a passer, I told Sir Alex they should be taking Charlie.
"When we played against them, Ferguson said he didn't realise he was that good.
"He ended up going to Liverpool, where it has not worked out, and he's gone on to another Premier League club (Stoke). I'm sure he'll be a star there as he's a top-class player."