Cape Town - Manchester United attacking midfielder Alexis Sanchez has been ruled out of their Premier League clash with Southampton on Saturday.
Kick-off is at 19:30 (SA time).
The Chilean striker suffered a hamstring injury in training on Thursday.
The 29-year-old former Arsenal attacker has found it difficult adjusting to Jose Mourinho's ultra-defensive style at the club this season.
He has struggled for game time and was left out of the United squad to face Young Boys in the Champions League on Tuesday.
A statement from the club read: "Alexis sustained a hamstring injury in training on Thursday which requires further investigation to confirm severity."
Sanchez has one goal and two assists in 10 Premier League games this season.
United are also set to face Arsenal on Wednesday evening at 22:00 (SA time).