The Gunners' senior team were required at their Colney training base for a "series of engagements" the day after their 1-0 Carabao Cup win over Doncaster Rovers. However, James Olley of the London Evening Standard reported Ozil and Sanchez failed to show.
It's alleged this kind of behaviour has led some Arsenal players to believe Sanchez and Ozil will soon leave the Emirates Stadium, with each of their contracts set to expire at the end of the current season.
Olley also wrote that the club said illness was the reason for both players missing the event, despite Sanchez playing the entire game against Doncaster. Arsenal manager Arsene Wenger also failed to mention any such fitness issues in a press conference held on the day in question.
Wenger and the club have persevered in trying to convince both to sign extensions as they remain valued members of the team.
Despite some debate among fans as to whether the pair should be sold or kept at the club, both Sanchez and Ozil continue to rake in plaudits and recently received nominations to this year's FIFPro 11:
According to Olley, the pair still have contract offers on the table but have nonetheless refused to sign, and Sanchez in particular came close to leaving for Manchester City in the summer.
Sky Sports Statto recently broke down the Gunners who have contributed most to Arsenal's goal count in the past five years:
A somewhat lacklustre start to the Premier League season will not have helped stave off any divide in the squad. The Gunners have lost two of their opening seven matches and sit fifth, six points off joint-leaders Manchester City and Manchester United.
Both Ozil and Sanchez will be free to discuss summer moves with potential suitors in January, at which point they will have entered the last six months of their contracts.
The underlying sense is that not only can the pair earn higher wages if they're to move but will also have a greater chance at silverware, a notion that won't go down well with their team-mates.
Failure to show up for September's sponsorship obligations illustrates a lack of care between two of the club's most valued assets.