In an apparent robbery attempt caught on camera in London, Kolasinac jumped out of a vehicle to confront the masked aggressors, who had pulled alongside the car on mopeds.
Turkish-German Özil and his Bosnian teammate Kolasinac were unharmed but did not play in subsequent preseason friendly matches. Arsenal decided that "following further security incidents which are being investigated by the police" they will not be traveling to Newcastle for Sunday's first match of the season.
"The welfare of our players and their families is always a top priority and we have taken this decision following discussion with the players and their representatives," Arsenal said in a statement Friday.
"We are liaising with the police and are providing the players and their families with ongoing support. We look forward to welcoming the players back to the squad as soon as possible."