It was first assumed to be a mutual decision, but it reportedly came to a head in a conversation about a coach.
Baker would not let a coach take the blame for the Reds season this year.
Reds general manager Walt Jocketty, in a year-end meeting about the team's 90-win season, said he intended to fire hitting coach Brook Jacoby, according to a report.
Baker immediately stuck up for Jacoby, saying that the team's performance was not his fault.
"If you want to fire someone, fire me,'' Baker reportedly told Jocketty.
This conversation was likely the final piece it took for Jocketty to fire him. Baker was a target of some fans and sabermetricians, leading him to ultimately become Jocketty's target.
The two are not close, and people close to the situation say their relationship was "distant" or even "strained." Baker couldn't have been sure Jocketty would take him up on his offer, but Jocketty did, and fired him instead.
"I wasn't testing anyone,'' Baker said. "I was just doing what I thought was right."
"Sometimes it gets to the point where you're always blaming the teacher [Jacoby]. Sometimes it's the pupils,'' Baker said.
He said the departure was bittersweet, but that he will pursue another opportunity elsewhere.
"It hurts. It hurts big-time," Baker said. "It's a double whammy being swept out of the playoffs, and two days later this."
He will still get paid by the Reds, as he has one year remaining in his contract -- a contract that Baker earlier negotiated to last one year but the team insisted on making two.