Pogba was taken off after 18 minutes against the Swiss team at Old Trafford and the French midfielder looks certain to miss United's Premier League clash at home against Everton on Sunday.
Source:
Reuters
13 Sep - 2:44 PM 

"I don't know. I just know from experience it's a muscular injury. In my experience, muscular injury stops you from playing for a few weeks, I think," Mourinho told the club's website (www.manutd.com).

"It looks for me, too, (like a hamstring injury) but I haven't spoken yet to the medical department."

Mourinho replaced Pogba with midfielder Marouane Fellaini, who headed in the opener on Tuesday before setting up Marcus Rashford's strike.

The Belgian is a contender to fill in for the Frenchman against Everton. "Squads are for this, squads are for injuries, squads are for suspensions," Mourinho said.

"We don't cry with injuries. So if no Paul for Sunday, we have Herrera, we have Carrick, we have Fellaini and we have Matic," he added.

League leaders United have made a strong start to the season with three wins from their first three games before a 2-2 draw against Stoke City. Everton have one win from four games.

(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Ian Ransom)