Arsenal will discover the full extent of midfield lynchpin Francis Coquelin's knee injury on Monday amid fears he is facing months rather than weeks on the sidelines. The French midfielder suffered the injury to his right leg during the first half of Arsenal's win over Chelsea. Arsenal medics fear he has suffered a recurrence of the medial ligament injury that kept him out for two months last season. Coquelin will have a definitive scan on Monday, but if the club's fears are realised the midfielder could be facing a fight to play again this calendar year. The 25-year-old left the Emirates Stadium in a knee brace on Saturday and manager Arsene Wenger admitted the injury looked 'bad'.