London - Manchester United goalkeeper Victor Valdes escalated his dispute with manager Louis Van Gaal on Thursday by posting pictures of himself with the club's Under-21 team, which Van Gaal had accused him of refusing to play for.
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Former Spanish international Valdes was left out of United's tour to the United States and told to leave the club because "last season he refused to play in the second team", the manager told reporters in Seattle.
But Valdes, who signed an 18-month contract with United in January, responded with a post on Twitter including mention of three Under-21 games and a picture of himself in the dressing-room with the message "...? #respect"
It is not the first time the pair have clashed. When they worked together at Barcelona in 2002, Valdes declined to play in a reserve game after being dropped and was fined.
Now his future is in doubt, just as United face renewed interest from Real Madrid in signing their number one goalkeeper David de Gea.