David De Gea is under growing pressure from Louis van Gaal to play for Manchester United against Barcelona tomorrow evening and to ensure that he is mentally prepared for the start of the season amid the uncertainty over his future.

The United goalkeeper, whose hopes of a move to Real Madrid this summer are fading, has missed the club’s first two tour matches in the United States with a mystery injury, for which he was sent to hospital in Seattle for assessment.

It is understood that De Gea complained of a back problem, but scans showed nothing untoward and Van Gaal reacted by instructing the Spain goalkeeper to take part in the warm-up before United’s game against San Jose Earthquakes on Wednesday.

At one point,