Washington finished first in the NL East both years with Baker as skipper.
Baker led the Nationals to a 95-67 record in 2016 and followed it up this season by going 97-65.
According to USA Today, Baker was pretty upset by the firing.
“I’m surprised and disappointed. They told me they would get back to me and I told them I was leaving town yesterday and they waited 10 days to tell me.”
The 68-year-old’s contract expired after the season.
“I really thought this was my best year,” continued Baker. “We won at least 95 games each year and won the division back-to-back years but they said they wanted to go in a different direction. It’s hard to understand.”