The 34-year-old joined the Blues in 2001 for £11m and has gone onto great success, winning the Premier League three times and the Champions League once, while also scoring over 200 goals for the club.
Ferguson told reporters: "Lampard is fantastic. Unbelievable. I don't think there's a midfield player who will ever do those 200 goals again.
"It is quite phenomenal. I think the guy has had a great career, I must say. We looked at him at West Ham when he was a young player.
"I think you now regret not doing it. Where else could I get 200 goals?"
Manchester United face Chelsea later today at Old Trafford.