Alexander Buttner’s agent has criticised Manchester United for their "unbelievable" failure to sign Fabio Coentrao on transfer deadline day, which meant that the Dutchman was denied a loan move of his own.
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United made a late approach for Real Madrid’s Portugual international, who they wanted to borrow for the season, but saw the move break down.
And Besiktas vice-president Ahmet Nur Cebi has said that the Turkish club had agreed terms with United to take Buttner on loan.
But David Moyes’ inability to bring in another left-back, despite spending the summer pursuing Everton’s Leighton Baines, resulted in Buttner staying at Old Trafford.
And his agent Alexander Bursac told Voetbal International: "It's unbelievable that Coentrao was not signed on time and, whether that is an error on the part of Real or United doesn't matter.
"We have received assurances of a loan. Alex is not necessarily looking for a guarantee of playing time, but he does not want to spend the entire season on the bench."
Celtic were also interested in a loan deal for Buttner, who United bought from Vitesse Arnhem for £3.9 million last summer.
The defender only started four league games last season but despite that, Bursac insisted: "Under Sir Alex Ferguson, Buttner was the up and coming man.
"He started playing in more games and was trusted in training. That sense of trust is not there now."
Buttner is yet to feature under David Moyes but was an unused substitute in Sunday’s 1-0 defeat to Liverpool.
However, the return of Fabio da Silva, who spent last season on loan at QPR, means he faces competition for the role of Patrice Evra’s deputy.