The Manchester United forward sustained the injury in a training session on Thursday and is set for up to a month out of action.
Manchester United star Alexis Sanchez is set for a spell on the sidelines after it was confirmed he has suffered a hamstring injury.
The Chilean has started just seven matches so far this season in a campaign that has been plagued by injuries.
Reports suggest Sanchez could face anywhere between two to four weeks on the sidelines, which means he is likely to miss next week’s clash against his former side Arsenal.
Having missed out on a place in the match day squad for United’s win against Young Boys on Tuesday, Sanchez was expected to be required again during the upcoming festive schedule.
Jose Mourinho’s side are to travel to the south coast to take on Southampton in their next match this Saturday, before they host Arsenal and Fulham in the space of three days next week.
They are also due to wrap up their Champions League group stage fixtures with an away tie at Valencia next month, before they travel to Anfield to take on Liverpool.
Mourinho was quizzed on the omission of Sanchez during the victory over Young Boys earlier this week, where he confirmed that the former Barcelona and Arsenal forward is not injured.
“No he is not injured, but it is quite curious because you always speak about the ones who are not playing,” the United boss said following the match.
“Today (on Tuesday) you had (Marcus) Rashford as a 9, that’s what you want, what you ask all the time, it’s what you had.”
Sanchez has just one goal to his name so far this season having lost his place in the side during the early stages of the campaign.