The Washington Nationals go for a series sweep over the host San Francisco Giants on homecoming day for pitcher Joe Ross in the finale of a three-game set between postseason hopefuls on Wednesday afternoon. The Nationals have received brilliant starts from Erick Fedde and Anibal Sanchez in the first two games of the series, helping Washington (60-53) move two more games ahead of San Francisco (56-58) in the National League wild-card chase. Ross (1-3, 8.10 ERA), who was born in the Oakland suburb of Berkeley, will be making just the second start of his professional career in San Francisco.