Washington @ Arizona preview

Last Meeting ( Aug 11, 2012 ) Washington 6, Arizona 5

Arizona is battling to stay in the National League West race, but Washington keeps getting in the way. The Nationals look for their ninth straight win and a three-game series sweep Sunday, while the Diamondbacks have slipped five games out of first in the NL West. The Nationals own the best record in the majors at 71-43, and they’re averaging 5.7 runs per game during their current winning streak. They’ve also won four straight against Arizona, which placed shortstop Willie Bloomquist on the 15-day disabled list, retroactive to Aug. 9, with lower back stiffness.

Washington is a major league-best 39-21 on the road, and their lineup continues to impress. Outfielder Jayson Werth hit leadoff for the first time this season Saturday, and he could stick there even after shortstop Ian Desmond (oblique) returns from the disabled list. Desmond took batting practice Saturday and could begin a rehab assignment this week. When he returns, Steve Lombardozzi will become a reserve player, with Danny Espinosa moving to second base. Werth could stay in the leadoff spot since he’s batting .311 and showing the ability to extend his at-bats.

TV: 4:10 p.m. ET, MASN2 (Washington), FS Arizona

PITCHING MATCHUP: Nationals LH Ross Detwiler (6-4, 2.99 ERA) vs. Diamondbacks LH Patrick Corbin (3-4, 3.53)

Detwiler is winless in his last seven road starts, primarily because of a lack of run support. He’s pitched well in his last two starts, giving up two runs over 14 innings and going 1-0 with a 1.29 ERA. Detwiler, who allowed one run over 6 1/3 innings against Arizona on May 3, hasn’t struck out more than five batters in a game since April.

Corbin made his second straight quality start Tuesday against Pittsburgh, giving up two runs over six innings. A second-round pick in 2009 by the Angels, Corbin has gone 1-1 with a 2.29 ERA in four appearances (two starts) at Chase Field this season. He also boasts a 42-to-18 strikeout-to-walk ratio in 51 innings.

WALK-OFFS

1. The Diamondbacks recalled RHP Bryan Shaw from Triple-A Reno and designated LHP Mike Zagurski for assignment.

2. Edwin Jackson recorded the 51st win by a Nationals starter this season Saturday. The team record is 52, set by the 2005 rotation.

3. The Nationals are 12-4 in one-run games against the Diamondbacks since 2005.