Laurent Koscielny refused to travel with Arsenal for their pre-season tour to America after becoming frustrated with the direction that the club is heading in, as well as the way his return from injury was handled last season.
The French central defender failed to board the flight which left on Thursday, after reportedly informing manager Unai Emery the previous day of his feelings.
The club responded by issuing an angry statement on their official website, citing their disapproval at Koscielny's behaviour.
"We are very disappointed by Laurent’s actions, which are against our clear instructions," the statement began. "We hope to resolve this matter and will not be providing any further comment at this time."
It had been thought that Koscielny's decision was based around his desire to move back to France, with Arsenal's captain said to have believed that an agreement was in place for him to be released from his contract this summer when the club failed to qualify for the Champions League
Club statement on Laurent Koscielny— Arsenal FC (@Arsenal) July 11, 2019
However, BBC Sport journalist David Ornstein claims that it is not just a desire to return to his homeland that caused Koscielny's no-show.
Arsenal have signed just one player so far during the transfer window, the 18-year-old Brazilian Gabriel Martinelli. This has left Koscielny questioning the club's ambition, as they prepare for their third straight year in the Europa League next season.
Moves for Wilfried Zaha
The 33-year-old is also said to be frustrated by the way he was rushed back in to action last season following a long-term achilles injury. Koscielny was forced to miss France's triumphant World Cup campaign in 2018 with the issue, but was brought back in to the Arsenal
Yet he played twice in three days upon his return, a feat that he was asked to do a further five times in the remainder of the season due to Arsenal's lack of defensive options. The experienced defender is believed to feel that this was an unnecessary risk, leading to further friction between himself and the manager.