Steve Bulpett of the Boston Herald reported those close to Bird and the Celtics knew he was dealing with emotional distress.
A source told the Herald that Bird was having "panic attacks and things like that. It wasn't a long-term thing, but everyone knew. The Celtics knew there was something going on and he was being treated."
Another person said: "This wasn't one of the domestic-violence situations you usually see where someone gets jealous for one thing and loses control. There was something deeper going on here with (Bird). This was a bad situation."
Bird was placed under a psychiatric hold after his arrest and stayed under the care of physicians until he was released last Thursday. He was then arraigned on counts of kidnapping and assault and battery before being released on $50,000 cash bond.
The Celtics released a statement saying they were "deeply disturbed" by the allegations.
"Most importantly, our thoughts are with the victim of this incident. The Celtics organization deplores domestic violence of any kind, and we are deeply disturbed by the allegations against Jabari Bird," the statement read. "Pursuant to Domestic Violence Policy in the NBA's labor agreement, matters of this kind are handled by the League Office, not the team, and so the Celtics will be working with both the league and local authorities to assist in their ongoing investigations. The team will have no further comment at this time."
Bird released a statement, per Bulpett, saying he was taking a break from basketball to deal with his mental health issues.
"I'm taking some time away from the team as I deal with my legal and medical issues," Bird said. "I apologize to my family, the Celtics organization, my teammates, the fans and the NBA for the unnecessary distraction that I have caused. The information that has been released does not tell the full story. I do not condone violence against women. I am hopeful that in due time and process, I will be able to regain everyone's trust."