After spending a couple of spells on loan at Sunderland, Evans has made huge progress in the last two seasons.
The Northern Ireland international has now made 64 first-team appearances for United, the latest coming in Sunday's victory at the Stadium of Light, and has proved himself good enough to stand in for Rio Ferdinand during the defender's increasingly frequent injury absences.
Although there has been no formal announcement from Old Trafford, Ferguson let slip at last night's player-of-the-year awards that Evans has agreed a new deal, which is expected to be confirmed in the coming days.
"Jonny has proved himself," said the United boss told MUTV.
"He has signed a new contract and helps to provide a good foundation for the club for a long time."
It is not believed Evans has actually put pen to paper yet but it is a measure of how highly the 22-year-old is rated at Old Trafford that Ferguson wanted him tied down to a new deal, with many seeing the Belfast-born player eventually becoming a club captain.