The pair held clear-the-air talks at United's Carrington training HQ on Sunday after 't-shirt gate'.
"Rio can play for two or three years," said Ferguson. "He has different issues from Paul (Scholes) or Ryan (Giggs) in terms of injuries over the last couple of years.
"He is not as quick as he was but that is not a big problem because his experience is important.
"He is still a great footballer and, even at 33, there is no reason why he can't stay on.
"We have always adopted that policy of offering one-year contracts, so we will see as the season progresses.
"I didn't even realise his contract was up. You are making me panic."