Manchester United forward Alexis Sanchez has suffered a hamstring injury, the club has confirmed.
Sanchez was forced out of training at Carrington on Thursday and is set for a scan on Friday. He is likely to miss Saturday's trip to Southampton and is also a doubt for former club Arsenal's visit to Old Trafford on Dec. 5.
A statement from United issued on Thursday night read: "During today's training session, Alexis Sanchez sustained a hamstring injury, which will require further investigation to confirm its severity."
Sanchez was left out of Jose Mourinho's squad for the 1-0 win over Young Boys on Tuesday with the United manager revealing afterwards the 29-year-old was omitted for tactical reasons rather than because of injury.
It was the second time the Chile international has been axed from the 18-man matchday squad after failing to make the bench for the 3-1 defeat at West Ham in September.
The injury to Sanchez's right hamstring is the latest blow since leaving the Emirates in January. He has scored once in 12 appearances so far this season and has started just one of United's last seven Premier League games.