The former Liverpool forward has been left out of the Saudi club’s league squad for the remainder of the season.
Although ineligible for domestic matches, Firmino can still feature in the Asian Champions League.
His omission has fueled rumors that he could seek an early contract termination, potentially allowing a move elsewhere.
Firmino was sacrificed to make room for January signing Galeno, with Saudi clubs limited to 10 overseas players.
On the situation, manager Matthias Jaissle said: "It was a difficult decision for the club and based on the rules. We appreciate him and he dealt with it professionally. He’s still one of our leaders."
Firmino himself posted a bible verse, saying: “10 Blessed are those who are persecuted for righteousness' sake, for theirs is the kingdom of heaven. 11 Blessed are you when people insult you and persecute you and say all kinds of evil against you falsely for My sake. 12 Rejoice and be glad, for great is your reward in heaven, for so they persecuted the prophets who were before you."