Willingham was ejected from the game after arguing vehemently with home plate umpire Bill Miller over a called third strike in the eighth inning.
Willingham threw down his batting helmet made contact with the umpire during the tirade, which earned him the suspension and a fine for "inappropriate conduct," MLB.com reported.
The A's said the 32-year-old clean-up hitter is appealing the suspension, during which the disciplinary actions will be put on hold.
Willingham has posted a .225 average with five home runs and 17 RBI this season.
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