Manager: Lloyd McClendon, first year Record: 72-60 Last 10 games: 6-4 Who to watch: 2B Robinson Cano (.325/.393/.469, 30 doubles, 12 HR, 71 RBIs); 3B Kyle Seager (.275/.344/.471, 26 doubles, 20 HR, 81 RBIs); RHP Felix Hernandez (13-4, 2.07 ERA, 0.89 WHIP); RHP Hisashi Iwakuma (12-6, 2.83 ERA, 0.98 WHIP) Season series vs. Nats (2013): Did not play Pitching probables Aug. 29: Felix Hernandez vs. Jordan Zimmermann, 10 p.m., MASN2 HD Aug. 30: Chris Young vs. Stephen Strasburg, 9 p.m., MASN2 HD Aug. 31: Hisashi Iwakuma vs. Tanner Roark, 4 p.m., MASN2 HD Series breakdown All season, the Nationals have gone into games knowing they don't need to score much to win. Now, Washington gets a taste of that when facing the only team that has a better ERA in all of baseball - the Seattle Mariners. The Nats open a six-game West Coast swing with three games at Safeco Field and will need to match zeros with the Mariners to have a shot at halting a three-game slide. If you need a reason to stay up late the next couple of nights, look no further than the fact that the series pits baseball's top two pitching staffs against each other. Seattle leads the majors with a 2.99 ERA while the Nats rank second at 3.13. The Mariners lead the American League and rank third in the bigs with a 3.30 starters' ERA and lead all of baseball with a 2.37 bullpen ERA. Their 10 blown saves are tied for the second-fewest in the majors. Seattle's starting staff is led by a trio of aces, all three of which are scheduled to take the mound in the series. The best of the best goes first, as right-hander Felix Hernandez faces Jordan Zimmermann in tonight's opener. The AL Cy Young contender ranks second in the AL and third in the majors with a 2.07 ERA while leading the AL (and ranking in the top three in the majors) with a .196 opponents' batting average and a 0.88 WHIP. He's also fourth in the majors with 204 strikeouts. By Hernandez's standards, he's struggled lately, going 0-1 with a 4.22 ERA over his last two starts, having allowed five runs in 10 2/3 innings. He pitched five and 5 2/3 innings over his last two outings, ending a streak of 16 straight starts going at least seven frames. That small setback has elevated the 28-year-old's ERA from 1.95 to 2.07. Former Nationals farmhand Chris Young pitches against Stephen Strasburg in the second game of the series. Back in the majors for the first time since 2012, Young is having a tremendous season, going 12-6 with a 3.17 ERA in 26 games (25 starts). The veteran right-hander has allowed three runs or fewer in 13 straight starts, but is coming off an outing where he allowed three runs on seven hits and five walks in just 3 2/3 innings. Right-hander Hisashi Iwakuma pitches opposite Tanner Roark in Sunday's series finale. Iwakuma would be the ace of most other pitching staffs, having gone 12-6 with a 2.83 ERA in 22 starts. He ranks seventh in the AL in ERA and third with a 0.98 WHIP, which also ranks fifth in the majors. But Iwakuma is coming off his worst start of the season, as he allowed five runs in 2 1/3 innings. In his 10 previous starts, he had gone 7-2 with a 1.63 ERA. Seattle's outstanding bullpen is led by six relievers that have pitched to ERAs of 2.45 or better in at least 47 appearances - closer Fernando Rodney (38 saves, 2.19 ERA), left-hander Joe Beimel (1.60 ERA) and right-handers Tom Wilhelmsen (2.06 ERA), Yoervis Medina (2.14 ERA), Dominic Leone (2.38 ERA) and Danny Farquhar (2.45 ERA). Like the Nats, the Mariners haven't needed a top offense to win games. Seattle ranks 11th in the AL with 528 runs, 10th with 105 homers, 13th with a .246 average and 15th with a .679 OPS. Even with that, the Mariners are 12 games over .500 and currently tied for the AL's second Wild Card. Second baseman Robinson Cano leads the lineup in his first season with Seattle. He's tied for third in the majors with a .325 average and ninth in the AL with an .862 OPS. Cano has 30 doubles, 12 homers and 71 RBIs. Third baseman Kyle Seager has also been a key contributor, as he leads the team with 20 homers and 81 RBIs, which ties him for 10th in the AL. He also has 26 doubles and an .815 OPS. Catcher Mike Zunino has added 19 homers and 48 RBIs, but is batting just .205/.261/.418. The Mariners have played well lately, going 15-6 over their last 21 games, during which time they have allowed more than four runs only twice. This will mark the first time the two teams meet since Washington swept Seattle in 2011 with two walk-off wins in three games at Nats Park. But now both teams have more at stake with both ranking among baseball's best, vying for playoff spots. It should be a stingy weekend in Seattle as the two teams match the two best sets of arms in the major leagues with more on the line.