Rio Ferdinand fears Manchester United could live to regret the decision to allow Nemanja Vidic to join Internazionale, and he admitted that his own future at Old Trafford remained uncertain.

Ferdinand made the comparison between Vidic and the former United favourite Jaap Stam, who was sold in 2001 to Lazio because Sir Alex Ferguson believed that his powers were on the wane. Stam, then 29, had also angered Ferguson with comments he made in his autobiography.

The Dutch centre-half went on to play at the highest level for a further six years – he also enjoyed spells at Milan and Ajax – and Ferguson would later admit that "in playing terms, it was a mistake" to sell Stam. Financially, Ferguson could argue that a fee of £16.5m for a player of that age who had struggled with an achilles injury was impossible to turn down.

United will get nothing for Vidic, who has signed a pre-contract to join Inter as a free agent in the summer and, at 32, he is older than Stam was when he departed Old Trafford. But Ferdinand still believes his long-time central defensive partner has something to offer.

"Only time will tell if Man United regret allowing him to leave," Ferdinand said. "Obviously Jaap Stam played on for quite a few years at a good level after he left Man United and the same thing could happen with Nemanja. He's a great player and it's a shame he had to leave."

Ferdinand is 35 and is also out of contract in the summer. He is determined to play on, ideally at United where he has spent the last 12 years. But he said that his situation would remain unresolved until the club appointed a permanent successor to David Moyes, who was sacked two weeks ago. Louis van Gaal is expected to be confirmed as United's new manager.

"I'm fit, I'm healthy and I want to continue playing," Ferdinand said. "I've spoken to a lot of mates of mine in the game and they all say the same thing – keep playing for as long as you can. I want to do that.

"The club at the moment is in a position where they can't really make any decisions about anything. For me to be saying that I want to do this or that is irrelevant. We've got to see who becomes the new manager and boxes will be ticked from there.

"I just want the best solution for the club. Whatever it is I'll respect it and, after that, I'm open to offers. I'd rather wait and see what happens at United and then there'll be a decision to be made."

Ferdinand was used sparingly under Moyes – he started only nine matches in the Premier League while the Scot was in charge – and it has clearly been a disastrous season for almost everybody at the club. Ferdinand, though, stressed the importance of looking forward.

"There's no point harping on about what David Moyes did and what went wrong," Ferdinand said at the launch of the BBC's World Cup coverage. "We've got to turn the page. You can't move forward if you keep looking back. A new manager will come in and he's the person we've got to get behind, to work with and make sure he gets it right.

"It's important everyone works together to continue the process of winning, as that's what we are. We're a team that's won lots of titles and cups and we want to get back to that. We have to work together to make sure the new manager has success for the club, himself and ourselves. It didn't work this time, but hopefully it'll work next time.

"It's been a disappointing season, 100%. The table doesn't lie. We're in a bad position and nobody expected us to go this way. It's for us, as players, to take responsibility, and if you asked anyone in the changing room they'd say we do take responsibility for our performances.

"Obviously, the powers that be decided to change the manager. Hopefully the new guy can come in and change the fortunes of the club."