Jordan Zimmermann aims to become the National League's first 14-game winner on Wednesday night when he gets the call for the second contest of a three-game set with the San Francisco Giants.

Zimmermann is 13-6 with a 3.10 earned run average in 23 starts this year, leaving him tied with St. Louis' Lance Lynn and Adam Wainwright for the most victories in the NL. The American League already has had four pitchers reach the 14-win mark.

The right-hander has just one victory over his last six starts as he has been dealing with a stiff neck. Zimmermann was tagged for 12 runs, 14 hits and four homers over just 8 2/3 total innings of consecutive losses to the Los Angeles Dodgers and New York Mets before a win at Milwaukee on Aug. 2. He hurled six scoreless innings on that day.

Zimmermann then faced off against NL East-leading Atlanta on Wednesday and lasted just four innings. He was charged with two runs on seven hits and two walks without a decision, logging 88 pitches.

The 27-year-old is 3-2 in six lifetime meetings with the Giants, posting a 3.19 ERA.

The Giants counter with Tim Lincecum, who has allowed two runs or fewer in four of his past five starts, a span that began with his no-hitter on July 13.

The righty has allowed three runs over his last three starts and is coming off a game versus Milwaukee on Thursday. Lincecum allowed just one hit and a walk over eight innings, striking out eight to claim a 4-1 win.

The two-time NL Cy Young Award winner improved to 6-11 with a 4.18 ERA in 23 starts this season.

"I'm just trying to stay within myself. I know I'm not blowing anyone away with a 95 mph fastball anymore. I have to use what I have and get the outs," Lincecum admitted.

Lincecum, 29, will make his ninth career start versus Washington and is 1-4 with a 5.68 ERA against the club.

The Nationals hope to add another loss to that total as they try to match their longest winning streak of the season; a five-game run from May 4-10.

Washington followed a three-game sweep of Philadelphia over the weekend by winning Tuesday night's opener 4-2. Adam LaRoche had the key hit, a tie- breaking, two-run homer in the sixth inning.

Ian Desmond had three hits and scored twice for the Nats, who have won four straight for the first time since July 4-7.

"I can't remember the last time when we put four wins together," said LaRoche. "It feels like it hasn't happened this year. We just have to build off of it and see where it takes us."

Washington outfielder Bryce Harper was held out of the starting lineup due to the flu, but was able to pinch-hit in the eighth inning. However, catcher Wilson Ramos had to come out of the game following a one-hour, 17-minute rain delay prior to the start of the fifth inning. Ramos aggravated a hamstring injury running to first base in the fourth.

The Giants had to scratch second baseman Marco Scutaro from the lineup due to a sore back, and his replacement in the lineup Joaquin Arias came through with a career-high four hits.

Arias scored twice, but did pop up in the eighth inning with the tying and go- ahead runs on base.

"I have no complaints with his game because he did everything he could do," said Giants manager Bruce Bochy about Arias. "We need more people to step up and we need them to do it now."

With the offense struggling, the Giants have lost two straight and seven of their last 10 games.

San Francisco won two of three over Washington at home in late May, but has lost six straight at Nationals Park.