The Oakland Athletics sit atop the American League West heading into their weekend series beginning Friday night against the visiting Washington Nationals, but they'll need to play better at home if they expect to hold on to the top spot in the West. The Athletics have lost six of their last seven at Oakland Coliseum and are 7-9 overall at home this season, the only first-place team in the six divisions with a losing record. Oakland is still waiting for third baseman Josh Donaldson to get untracked - he's 3-for-20 in his last six games to drop his average to .262, well off the .300 clip he posted for most of last season.Nationals outfielder Jayson Werth has raised his batting average from .247 to .313 in the last 12 games, courtesy of 21 hits in his last 51 at-bats. Denard Span is also heating up in the leadoff spot for Washington, raising his average to .250 with a pair of hits in Wednesday's win against the Los Angeles Dodgers after dipping as low as .208 on April 22. With Adam LaRoche maintaining his consistency in the cleanup spot, the Nationals should be able to match up well against Oakland's pitching.TV: 10:05 p.m. ET, MASN 2 (Washington), CSN California (Oakland)PITCHING MATCHUP: Nationals RH Doug Fister (2013: 14-9, 3.67 ERA) vs. Athletics LH Tommy Milone (0-3, 5.86)Fister is set to make his season debut with his new team after missing all of last month with a strained lat muscle. He has reached double figures in wins in each of the last three seasons and should be a nice boost for a pitching staff that entered Wednesday tied with the Athletics for the third-lowest ERA in the majors at 3.06. Fister has some experience pitching at Oakland Coliseum from his years with the Seattle Mariners, owning a 2-3 mark with a 2.41 ERA in six career starts.The Athletics haven't won in Milone's five starts this season, leaving his spot in the rotation in jeopardy if he continues to struggle. He took another step back Saturday against the Boston Red Sox, surrendering three home runs in four innings of a 6-3 loss, but in his defense Oakland has scored only 16 runs in his five appearances this season. Milone is 6-4 in his career in interleague play, posting one of his two complete games against the Los Angeles Dodgers in June 2012 in Oakland.WALK-OFFS1. The Nationals optioned 1B/OF Tyler Moore to Triple-A Syracuse to make room for Fister. 2. Washington's relief pitchers have amassed a 2.11 ERA, third lowest in the majors.3. The Nationals have outscored the opposition 82-45 after the sixth inning this season.PREDICTION: Nationals 7, Athletics 3