The Washington Nationals have been shut out twice in the last five games and Saturday they'll be up against the staff ace for the host Oakland Athletics when the teams meet in the middle game of their three-game series. The Nationals were blanked in the series opener Friday night as left-hander Tommy Milone shut out his former team on two hits through eight innings. Meanwhile, the Athletics have delivered back-to-back shutouts from their pitching staff.The third through fifth hitters for the Athletics - Josh Donaldson, Brandon Moss and Yoenis Cespedes - combined to go 6-for-14 in Friday's opener, and Moss, Cespedes and John Jaso hit home runs, marking the 21st time Oakland has scored at least four runs this season, of which they have won 15. The Athletics may have to go another game without center fielder Coco Crisp, who sustained a strained neck during Wednesday's doubleheader against the Seattle Mariners and sat out Friday. Former Athletic Scott Hairston had a pair of hits in Friday's game to up his average to .500 in limited action this season for Washington.TV: 9:05 p.m. ET, MASNsports 2 (Washington), CSN California (Oakland)PITCHING MATCHUP: Nationals RH Tanner Roark (2-1, 4.17 ERA) vs. Athletics RH Sonny Gray (4-1, 1.91)Roark will look to bounce back after his worst start of the season, surrendering seven runs and seven hits in four innings of a 7-2 loss Saturday against the Philadelphia Phillies, blowing up an ERA that was 2.76 at the start of the game. The second-year pitcher had thrown a three-hit shutout in his previous start, a 4-0 win against the San Diego Padres on April 26. Roark needs to prove he can pitch effectively on the road, as he's 4-0 with a 0.26 ERA at home in his career and 5-2 with a 4.07 mark on the road.Gray has cemented himself as the ace of the Oakland staff by winning American League Pitcher of the Month honors for April. He came into the weekend tied for second in the AL in ERA and has gone at least six innings and allowed three earned runs or fewer in all seven starts this season. The Nationals will be just the second interleague opponent Gray has faced in his two-year career.WALK-OFFS1. Oakland C Derek Norris is 19-for-38 in his last 14 games.2. Athletics RHP Fernando Rodriguez pitched the ninth inning Friday, his first appearance since Oct. 3, 2012.3. The Nationals have committed 32 errors, third most in baseball this season.PREDICTION: Athletics 3, Nationals 1