Nasri, who was in the final year of his contract at Arsenal, joined Manchester City in a £24million deal earlier this week.
“We are all in the same boat,” said Ferguson.
“When a player gets to the last two years of his contract you have an issue. One: you persuade him to sign a new contract. Two: he doesn’t want to sign a new contract. Three: When he gets to that last year it is almost inevitable you have a problem.
“We have had issues at times with players getting into the last year. We are not alone.
“When a player is not going to sign a contract you can threaten to keep him for another year and not get anything for him or capitalise and get the money.
“It is sensible to take the money.”