England full back Luke Shaw is a doubt for the resumption of Manchester United's Premier League campaign against Arsenal after playing through the friendly international win over Scotland with a hamstring injury.
The 19 year old suffered a recurrence of a hamstring problem which forced him out for the first month of the season but played on until the 66th minute before being replaced by Kieran Gibbs at Celtic Park.
Shaw is now a major doubt for United's trip to the Emirates Stadium to face Arsenal on Saturday and becomes the latest addition to an injury list which also includes Angel di Maria, who picked up an ankle problem in Argentina's friendly loss to Portugal.
Speaking following England's 3-1 win over Scotland, Shaw told Sky Sports: "I picked up a few knocks during the game but my left hamstring, which I did at the start of the season, I could feel a little bit as well.
"We [me and manager Roy Hodgson] had a discussion at half time whether to bring me off but it was a game I didn't want to come off in.
"I played the extra 15 minutes and obviously he [Hodgson] decided to sub me off."
Asked about his fitness for United's game with Arsenal, Shaw added: "We'll have to wait and see whether I'll be fit."
The former Southampton defender becomes the fifth different United player to be injured during the international break, with David de Gea, Michael Carrick, Daley Blind and Di Maria all adding to a growing crisis at Old Trafford.
United face being without as many as 12 first team players for the resumption of the season, with Ashley Young, Jesse Lingard, Radamel Falcao, Rafael da Silva, Phil Jones, Jonny Evans and Marcos Rojo all facing an extended spell out.
And the additional blow regarding Di Maria and Shaw comes less than 24 hours after executive vice-chairman Ed Woodward stated the club had no plans to enter into the market in the January transfer window after a record summer of spending upon the appointment of new manager Louis van Gaal.