Nationals-Mariners Preview

The Washington Nationals were cooled off in the opening series to their nine-game road trip but have quickly gotten back in the groove in Seattle.

The Nationals will try to leave Safeco Field with a three-game sweep Sunday and head into a potentially pivotal series with some considerable momentum.

Washington (77-57) had won 12 of 13 before getting swept in three games in Philadelphia this past week. The Nationals have rebounded with a pair of victories in Seattle, and Jayson Werth hit a two-run homer for the second straight game in a 3-1 victory Saturday.

The win, coupled with Atlanta's loss to Miami, pushed Washington's lead atop the NL East to seven games and moved it two ahead of the Los Angeles Dodgers for the NL's best record. The Nationals conclude their trek with three games against the Dodgers beginning Monday.

Tanner Roark (12-8, 2.81 ERA) will seek to help his club pad its leads with another solid outing. The right-hander has a 2.10 ERA in his last four starts but took a 3-2 defeat in Philadelphia on Monday despite giving up two runs in six innings.

"I felt good, I felt confident," said Roark, who is 5-2 with a 1.90 ERA in his last nine road starts while holding opponents to a .191 batting average.

Roark will make his first start against Seattle, which is 1 1/2 games out of the second AL wild-card spot. He was 1-1 with a 1.03 ERA in first four interleague starts before giving up five runs in 6 1-3 innings in a 7-3 loss to Baltimore on Aug. 4.

Chris Denorfia is one of two active Mariners players to have faced Roark and the only one to get a hit, going 1 for 4. Logan Morrison is 0 for 2 with a walk versus the Nationals right-hander.

He'll face Hisashi Iwakuma (12-6, 2.83), who had his own string of impressive outings snapped last Sunday in Boston. The right-hander was charged with five runs in 2 1-3 innings, the briefest start in his career, but avoided his first loss since Aug. 3 when Seattle (72-62) rallied for an 8-6 win.

Iwakuma had a streak of 17 2-3 scoreless innings snapped and was 3-0 with a 0.42 ERA in his prior three starts.

"He just didn't have it," manager Lloyd McClendon told MLB's official website. "He's human."

Iwakuma will carry a 22-inning scoreless interleague streak in his first start against Washington. He's pitched 15 shutout innings in two matchups against NL teams this season, including a 5-2 win in Philadelphia on Aug. 19.

All three of his previous starts against NL teams took place on the road. He's 4-1 with a 1.73 ERA in his last five outings at Safeco Field.

Asdrubal Cabrera is 1 for 10 with three strikeouts lifetime against Iwakuma.

McClendon could return to the Mariners dugout for Sunday's series finale after missing the past two games to attend his daughter's wedding in Indiana. Bench coach Trent Jewett has led the team the past two games.