Paul Pogba has reassured Manchester United fans that "all will be fine" amid fears he could be sidelined for up to six weeks with a hamstring injury.

The France international was made captain for United's return to the UEFA Champions League against Basel at Old Trafford but lasted just 19 minutes of his side's 3-0 win.

Pogba hobbled off in clear discomfort and was seen leaving Old Trafford on crutches, with manager Jose Mourinho admitting that he expects the midfielder to be out for "a few weeks".

United has yet to put a timescale on his recovery but the latest reports suggest he will miss at least a month of action, although Pogba himself appears determined to stay optimistic.

He posted a picture of himself – in which he is still using crutches – standing with his mother and brothers Florentin and Mathias, with the caption: "When you know all will be fine."

Pogba seems certain to miss the Premier League meeting with Everton on Monday (AEST) and the EFL Cup third-round tie at home to Burton Albion next Thursday (AEST).

He is also a doubt for further league matches against Southampton and Crystal Palace and the Champions League trip to CSKA Moscow on September 27, as well as the clash against Liverpool at Anfield on October 14.

The former Juventus star could also miss France's final World Cup qualifiers against Bulgaria and Belarus on October 7 and 10 respectively.