Washington @ San Francisco preview

Last Meeting ( Aug 14, 2015 ) Washington 5, San Francisco 8

Bryce Harper might be leading the NL MVP race, but the Washington Nationals are going to need more than their dynamic right fielder to overtake the NL East-leading Mets. The Nationals have lost four straight and sit 4 1/2 games behind the Mets heading into Saturday’s contest against the host San Francisco Giants, who are 2 1/2 games back of the first-place Dodgers in the NL West.

The Nationals aren’t about to panic, but they're 10-18 since the All-Star break and struggling to produce offensively aside from Harper, who belted his 30th home run in Friday’s 8-5 loss. “There are 40-some games left,” infielder Danny Espinosa told the Washington Post. “We have to win. We can’t let this slip any further.” Washington pulled within 6-5 on Harper’s fifth-inning blast Friday, but five Giants relievers blanked the Nationals over 4 1/3 innings to preserve the win. San Francisco’s bullpen has allowed three hits over 8 1/3 scoreless innings in the first two games of the series and might have an emerging star in rookie Josh Osich, who has yielded one earned run in his first 12 appearances.

TV: 10:05 p.m. ET, Fox Sports 1, MASN (Washington), CSN Bay Area (San Francisco)

PITCHING MATCHUP: Nationals LH Gio Gonzalez (9-4, 3.50 ERA) vs. Giants RH Jake Peavy (2-5, 3.75)

Gonzalez has been outstanding over his last eight starts while going 5-0 with a 1.48 ERA. The 29-year-old is coming off his best start of the season after tossing eight scoreless innings in a win over the Dodgers on Monday. Justin Maxwell is 4-for-11 with a home run against Gonzalez, who is 3-2 with a 2.40 ERA in eight career starts against San Francisco.

Peavy has gone 2-3 with a 2.74 ERA in seven starts since coming off the disabled list on July 3, but has completed seven innings only once during that span. The three-time All-Star allowed two runs over five innings in a 2-0 loss to the Cubs on Sunday. Yunel Escobar is 2-for-17 against Peavy, who held the Nationals to two runs in 6 1/3 innings on July 3 and is 4-6 with a 3.79 ERA in 13 career games (12 starts) against Washington.

WALK-OFFS

1. Washington is 42-19 when scoring first.

2. The Giants have won 11 of their last 13 games at AT&T Park.

3. Harper is the first left-handed hitter to have 30 home runs in a season at age 22 or younger since Boog Powell in 1964.

PREDICTION: Nationals 7, Giants 2