Manchester United are sweating over the fitness of defender Phil Jones after the 22 year old limped off towards the end of England's 2-0 win over Switzerland in Basel with a hamstring injury.
Jones was replaced by Phil Jagielka after 77 minutes at St Jakob Park and was visibly disappointed as he left the field to receive treatment.
The centre-back will likely be assessed by United officials upon his return to Old Trafford on Thursday before a decision is made over his fitness for the Premier League visit of Queens Park Rangers.
United's official website wrote of the injury: "Jones limped off with what looked like a hamstring pull 13 minutes from time, but it had no impact on the overall result as England held out for the win."
The blow could leave United short of defenders for the resumption of the Premier League season and further expose Louis van Gaal's transfer policy, which focused on adding forward players rather than replacing a number of key defensive departures in the summer.
Both former club captain Nemanja Vidic and Rio Ferdinand left the club but only Argentine Marcos Rojo was signed as a replacement and the loss of Jones will draw further scrutiny over Van Gaal's strategy in the transfer window.
With Chris Smalling also out injured United could face Harry Redknapp's QPR with just three senior centre backs available, with Jonny Evans, Tyler Blackett and Rojo expected to line up in the club's much-scrutinised back three.
Van Gaal did make two signings on deadline day in the transfer window in the form of Daley Blind and Radamel Falcao but remains short in the club's problem position at the back.
Jones has been ever-present for United in the league this season, playing every minute of their opening three games against Swansea City, Sunderland and Burnley as part of a controversial defensive shape.
Though United have encountered problems adapting to a new system, Jones – speaking before picking up an injury on international duty – is confident the club can adapt.
"I personally enjoy the system," he said. "When everyone is working well together and knows what they should be doing on the pitch then it certainly works and is very difficult for teams to play against.
"I think the more we train and play, the more people understand their role on the pitch."