London, Nov 30 (IANS): Manchester United's Chilean international forward Alexis Sanchez will be out of action "for a long time," after suffering a hamstring injury in training, coach Jose Mourinho said on Friday.

The club had previously issued a statement on Thursday saying Sanchez was injured and that they would carry out tests to see how serious the injury was. But speaking to the press ahead of the weekend Premier League trip to play Southampton, Mourinho said he expects to be without the player for a 'long time', reports Xinhua news agency.

"There are "no scans yet, but the player is experienced and he knows what the injury is. And also, from the top of my experience; the painful scream, and the way the injury happened, I know that it is going to be for a long time. It is not a little muscular injury that (will heal), in one week or 10 days," he insisted.

"So, I think Alexis has what I used to call an aggressive muscular injury," concluded Mourinho.

Sanchez has so far had a disappointing season at home, scoring just one goal in the Premier League in 10 appearances and less than 500 minutes of first team football despite his high wages.

The Chilean has fallen behind others such as Marcus Rashford, Romelu Lukaku and Anthony Martial in the pecking order to lead the United attack.