Wayne Rooney said he was "gutted" Friday after a hamstring injury forced him out of Manchester United's Asian tour on the very first day with questions still unanswered about his future.
The England striker insisted the small tear, which flared just hours after United touched down in Bangkok and looks set to rule him out for a month, was not serious.
But Rooney's departure will not help new boss David Moyes's attempts to win over the highly paid star, who has not confirmed his intentions after departing manager Alex Ferguson said he had asked for a transfer.
"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," Rooney wrote on his Facebook page.
Rooney will now miss United's friendlies in Thailand, Australia, Japan, Hong Kong and Sweden, and is in doubt for the Community Shield on August 11 and even the Premier League opener at Swansea on August 17.
The 27-year-old Liverpudlian might also be sidelined for England's friendly against Scotland on August 14.
The injury, announced in a two-line statement on the club website, comes after Moyes said Rooney was in his best shape in years and spoke glowingly about his relationship with his former Everton protege.
"I have met Wayne two, three, four times," he told talkSPORT radio this week. "A lot has been said about myself and Wayne over the years but we have a really good relationship."
Moyes added: "I will say he is training great. They are telling me it is the best shape they have seen him in for a long time."
Reports have linked Rooney with possible moves to Arsenal, Paris Saint Germain and Chelsea, who coincidentally arrive in Bangkok on Friday at the start of their pre-season Asian tour.
Returning manager Jose Mourinho has signalled his intention to sign a new striker to complement Fernando Torres and Romelu Lukaku, who is back after a successful loan spell at West Bromwich Albion.
But former United defender Gary Neville said Rooney -- who came close to leaving two years ago -- belonged at the club, and expressed hope they would sort out their differences.
"I think Wayne Rooney and Manchester United go together," Neville said, according to Britain's Daily Telegraph.
"He has to make his own mind up. The club will have a part to play in that. One thing about United, they never panic in situations, they always do things in a controlled manner.
"Although there have been rumblings about Wayne, he has come back into pre-season without much of a fuss. I think it'll unfold in the next few weeks."
Rooney joins a number of players on the sidelines of United's tour, which is a rare chance for Asian fans to catch the team in action with tickets on sale even for their training session later on Friday.
Captain Nemanja Vidic was among four players missing from the initial tour party through injury, while Robin van Persie, David de Gea and Shinji Kagawa are all set to arrive later in the trip.