As you are probably already aware, Macha is out:
Two days after the A's were eliminated from the postseason, Ken Macha was fired as the team's manager, because of what general manager Billy Beane described as "a disconnect on several levels.''
Though Beane was careful not to spell out that disconnect, emphasizing during a news conference Monday that he alone was responsible for Macha's ouster, the primary reason the team parted ways with a man with the second-highest winning percentage in Oakland history was that a growing number of players had issues with Macha.
From the same article, Susan Slusser quotes a number of suddenly vocal A's players expressing displeasure or at least admitting there was a problem. Surprisingly the most critical player appeared to be Kotsay, who claimed that players "...didn't have the same feeling about the manager as they did at the start of the year..." and that he felt "...disrespected..." when Macha questioned his injury. Most damning of all Kotsay stated "...we didn't play for him." Zito, Kendall, and Haren all sounded off negatively on Macha. But I think Chavez summed it up perfectly:
"Deep down inside, I think he cared about the players, he just didn't have a good way of communicating."
To quote my father, Management 101: Communicate, communicate, communicate - back your people, and let them know you back them.
A manager's greatest duty is to manage people and relationships - it seems from reading these reports that Macha failed in that respect.