According to CBS Sports, this whole brawl started when Adam Eaton of the White Sox hit a one hopper back to the mound. Royals pitcher Yordano Ventura delayed and stared at Eaton. Eaton said an obscenity to Ventura who yelled back before throwing to first for the out. The benches cleared, leading to the brawl.
Overall five players were ejected including both starting pitchers, along with Sox pitcher Jeff Samardzija, Royals pitcher Edinson Volquez, and Royals outfielder Lorenzo Cain.
I'm sure these players will have some suspensions coming. Being a Tigers fan it couldn't have come at a better time as the Tigers have both teams coming up on the schedule.