Dembele's future at as a Barça player was already under scrutiny over concerns about his professional attitude led to a recent meeting between president Josep Maria Bartomeu, a handful of other top club officials and the player's agent.
According to AS, Dembele stayed up late into the night while gaming with friends on a Wednesday night and forgot to set an alarm for the following morning. The club was apparently unable to reach him until 11.30am, half an hour after the scheduled session had got underway.
The report suggests that Dembele gave an upset stomach as the cause of his absence, prompting the club to send a doctor to examine the 21-year-old World Cup winner.
It is said that a build up of minor indiscretions, such as lateness and carelessness, are chipping away at the confidence that teammates and coaching staff have in Dembele, who was bought from Borussia Dortmund for a monster fee potentially rising to €145m just last year.
It was noted last week that Barcelona were concerned Dembele doesn't have a strong enough local support network to help him stick to his vital routines. His agent, for example, is based in London, and his mother is not with him in Catalonia either.
And while AS explains that Dembele is not out sampling Barcelona's nightlife, his 'marathon' gaming sessions with a 'troop of pals' are still a major cause for concern.
According to Sport, Barça have issued an 'ultimatum' to Dembele, making it clear that he needs to change his attitude and 'understand' what it means to play for the club or he will never be able to perform to the highest level that is expected and demanded.
Dembele has recently been linked with Premier League pair Arsenal and Liverpool ahead of the January transfer window, although a Daily Mirror