Dembele ended defeat against Athletic Bilbao at the San Mames with muscle problems which were clear on television as he felt his leg as he walked off.
The Frenchman finished the game but the discomfort continued, with club medics setting an appointment for Saturday morning to perform tests to understand the extent of his injury.
Those involved were left stunned when the winger did not turn up, reports Marca.
They tried to get hold of the Frenchman, but both medical staff and coaching staff were furious, remaining angry when Dembele eventually arrived on Monday to undergo the tests.
The results showed a tear to his left hamstring which could rule him out for five weeks and the club, right through from medical staff to directors and even his own teammates, are furious with the lack of a reaction from the player.