Manchester United manager David Moyes is keen to sign young defender John Stones from his old club Everton, [football] direct news understands.The 19-year-old centre-back has been in excellent form since becoming a regular for the Toffees in the second half of this season, attracting reported interest from the likes of Arsenal and Chelsea.A club source now claims that United will also hope to join the running to sign the England Under-21 international, as they look to strengthen at the back next season with Nemanja Vidic set to leave the club for Inter Milan.The injection of some youth into United’s ageing backline would certainly be a priority for Moyes, who has endured a difficult first season in charge at Old Trafford since leaving Goodison Park.A number of Moyes’ former players at Everton have been linked with United since his move, such as Leighton Baines and Ross Barkley, while Marouane Fellaini did eventually follow the Scot from Merseyside to Manchester late on in the summer transfer window.Stones now looks to be the latest Everton star to attract interest, and if he maintains these fine displays it would be no surprise if other big clubs joined the chase for his signature.