I don't know about that (in bold^^). Firing someone for losing in game 5 in the best of 5 series after winning almost 100 games? He has been there only 2 years! I understood why they fired Matt Williams. They had a very good team and did not make the playoffs. And Williams seemed to be losing the team. That was not the case with Baker. (At least not that I know of.)
As I wrote before, it is hard to win when there is no stability at the managerial position. Buster Olney reported today that the Nationals have had 6 managers in the last 10 years. Bryce Harper is 25 or 26 -- the next manager will be his 4th in his short career. It is unfortunate given how well they have played in the last 2 years. Olney also said that the Nationals owners don't want to pay their managers. No security. Low pay. Why would a good manager want to coach there!