Ssir alex Ferguson has failed to end speculation that Nemanja Vidic could leave Manchester United this summer.
The centre-back, 28, has been linked with a move away from Old Trafford for more than a year and has been targeted by Real Madrid, as well as both Milan clubs.
His representatives claimed he would make a decision about his future after the World Cup but he has not made any indication of his plans.
Along with the likes of Wayne Rooney and Patrice Evra, Vidic, who has continually denied claims that his wife, Ana, is unhappy in Manchester, has two years remaining on his contract, meaning United could be forced to cash in if Real Madrid make a bid.
Vidic is due to make his first United appearance of the pre-season with the club's other World Cup players when Ferguson's side face an Airtricity League XI in Dublin on 4 August.
Ferguson has previously been quick to stamp out talk of Vidic moving on but said after his team's 1-0 win over Philadelphia Union, when asked to clear up Vidic's situation: “I can't clarify it at all.”
Ferguson was asked if he thought the Serb would be at United next season and would only add: “I believe so.”
With continuing doubts about Rio Ferdinand's fitness, losing Vidic, who has been an outstanding performer since joining from Spartak Moscow in 2006, would be a considerable blow.
Ferguson is not short of defensive bodies, with Jonny Evans, Wes Brown and John O'Shea being joined by Chris Smalling this summer but will be desperate to keep hold of the reassuring presence of Vidic.
While Gabriel Obertan's goal secured a 1-0 victory over Philadelphia, which followed Friday's 3-1 win over Celtic, Ferguson has also been impressed with the development of youngsters Danny Welbeck (pictured) and Tom Cleverley during the tour of the USA.
Striker Welbeck had a stint with Preston ruined by injury last season while midfielder Cleverley spent the campaign at Watford and Ferguson now wants the duo to join Premier League clubs on loan in the new campaign.
“This is going to be a big season for Danny because for the last three years he has not had a consistent run of games,” Ferguson said.
“One of the things about Danny that may have caused the injury is that he is still growing. He has a weakness in his legs with the speed he is growing.
“He is about 6ft 2ins and a bit now. He has sprouted up in the last year and a half so he needs consistent football.
“He needs to play all the time and that is one of the reasons we are considering sending him on loan again to a Premier League team.
“Tom is a very talented boy. He is going to be a very good footballer and we are also considering putting him on loan to a Premier League team.
“He improved tremendously in his spell at Watford last year. He has just come back and can play anywhere in midfield, which is always an advantage.”
Cleverley is thrilled to playing alongside Paul Scholes and Ryan Giggs and believes the two veterans can only help his development.
He said: “Playing for United and alongside someone like Scholesy is what every young lad dreams of. He is a great mentor for me — I look to him every day in training and he is definitely someone I can learn a lot from.
“The likes of Scholesy and Giggsy always have a picture in their heads about what they want to do with the ball and their first time passing is second to none. ”