Unsettled forward Wayne Rooney is to return home from Manchester United’s pre-season tour – just one day after the club flew almost 200 players and staff out for the first leg in Bangkok. The England forward, who has been persistently linked with a move away from the club this summer, has suffered a grade-two hamstring injury, effectively a small tear.  Rooney said on Facebook: ‘Gutted to have picked up a niggling injury especially as training was going so well, heading back to Manchester to have it assessed fully but early indications are nothing to worry about.A statement said: ‘Following a scan this evening on a hamstring injury sustained in training, it has been decided that Wayne Rooney should return home immediately for further assessment and rehabilitation.‘It is anticipated he will be unavailable for selection for a month.’Rooney will spend the next two-and-a-half weeks working on his own with medical staff at United’s Carrington training centre after breaking down with a hamstring  tear just minutes into United’s first training session in Thailand.He will now focus on being fit for the start of United’s competitive season, against FA Cup holders Wigan in the Community Shield at Wembley on August 11.The news that Rooney has left United’s tour is sure to provoke speculation, with the player still to reveal whether he would like to remain at Old Trafford this season. United boss David Moyes retains a firm stance, saying that Rooney is not for sale under any circumstances - although the manager has passed up repeated opportunities to confirm that the player wants to stay at the club. Yesterday, Moyes told talkSPORT: ‘The club has already stated that Wayne is staying and is not for sale. I have met Wayne two, three, four times and he’s here every day. I have of course met him long before on many occasions.There has been a lot said about Wayne and myself over the years but we have a really good relationship. I have got him back to Goodison Park several times over the last few years.  ‘Wayne came up to my house and I came up to his house to meet him and have a chat. He is training great. The team here are telling me that it’s the best shape they’ve seen him in for five years so I am taking it as a positive. ‘We have stated he is not for sale and I am going to try to get the best Wayne Rooney that I possibly can.’