Alexis Sanchez walked out of training and was involved in a bust-up with angry team-mates days before being dropped for Arsenal's trip to Liverpool.
he episode casts further doubt over Sanchez's future, with Paris Saint-Germain the front runners ahead of Juventus to sign the Chile striker this summer, amid mounting concern over his failure to sign a new contract.
Wenger claimed after Saturday's 3-1 defeat at Liverpool that Sanchez had been dropped for tactical reasons, but it is believed that it came on the back of an incident that disrupted preparations for their trip to Anfield.
It is also understood that there has been a growing sense within Arsenal that their leading scorer has been behaving selfishly with so many public displays of frustration.
Matters appear to have come to a head last week, when it is alleged that Sanchez walked off the training pitch mid-session, for which a number of his team-mates confronted him in the changing room.
Sources claim a row then erupted over Sanchez's attitude and Wenger decided to put the 28-year-old on the substitutes bench at Anfield.
Although the decision has received an avalanche of criticism from supporters, pundits and former players, it is believed many Arsenal players back Wenger's stance.
Mesut Ozil also missed the Liverpool defeat through illness, although it is believed the German may have been benched at Anfield as well. Ozil's form has dipped and, like Sanchez, he has just over a year left on his contract and is yet to sign another.
Although Sanchez's team-mates are respectful of his work ethic and playing qualities, there has been irritation at how he has repeatedly drawn attention to his frustrations.
As well as throwing his gloves to the floor following the 3-3 draw against Bournemouth, he made a public show of annoyance at being substituted after scoring when Arsenal were beating Swansea City 4-0. Wenger was keen to give Danny Welbeck the last 11 minutes of match time following almost a year out with a serious knee injury.
Sanchez also berated Alex Oxlade-Chamberlain during the 5-1 beating at Bayern Munich and, as the inquest continued, there was a feeling at the club that it was Sanchez rather than Oxlade-Chamberlain who was not following the game plan.
Wenger made an unconvincing attempt to explain Saturday's decision with reference to wanting to go "more direct" and "win the balls in the air". He did also then hint at wider considerations and it remains to be seen if Sanchez will start tomorrow against Bayern Munich.
Asked if the Sanchez decision was "made for the team", Wenger cryptically said: "I will explain that later one time. If you make a decision, you make a decision. People are always emotional in their analysis to this kind of decision. I believe it's down to the collective performance."
Wenger was also adamant that the situation was "not at all" linked to Sanchez's contract standoff, but looming in the background is firm interest from Paris Saint-Germain and Juventus. It is understood that Arsenal's contract offer to Sanchez is worth around £180,000 a week, but he will be conscious of the certainty of better deals elsewhere.
If Saturday was an attempt by Wenger to show that no player is bigger than the team, it initially backfired. Arsenal were terrible without Sanchez in the first-half and improved in the second when the former Barcelona forward provided the assist for Welbeck's goal.
Aside from the FA Cup win over non-league Sutton, it was Arsenal's fourth defeat in only five matches. They have dropped out of the Champions League qualifying places and, given that their form is the worst of any top-six contender, Wenger's record of 20 straight top-four finishes is in serious peril.