By NICOLINO DIBENEDETTO
(AP) -- The Washington Nationals' postseason chances have taken a serious dent of late, and that may only continue at Citizens Bank Park.
Giving the ball to Gio Gonzalez, however, may improve their chances.
Gonzalez attempts to continue his success against the Philadelphia Phillies and help the Washington Nationals earn a rare road win against their NL East rivals Tuesday night.
Washington (69-68) looked to be a viable postseason contender after winning 14 of 19, but the team has since dropped three of four.
The Nationals are 7 1/2 games back of Cincinnati for the NL's second wild-card spot with 25 to play.
The offense is letting them down lately, going 5 for 30 (.167) with runners in scoring position. That includes failing to convert on three such opportunities during Monday's 3-2 loss to open this three-game series.
"That was really a tough one; it really hurt," manager Davey Johnson said. "It was like a stab in the heart."
Washington has dropped 11 of its last 15 games at Citizens Bank Park, batting .218 while the rotation has compiled a 4.03 ERA.
Gonzalez (8-6, 3.56 ERA), though, has been a bright spot against the Phillies (63-75), going 4-1 with a 2.31 ERA in six starts. Five have come in Philadelphia, where he's 3-1 with a 2.53 ERA and Washington has won four of those games.
The left-hander, third in last year's NL Cy Young Award voting, was superb in his most recent game there July 10, yielding one run in seven innings of a 5-1 victory.
Following that matchup, Gonzalez went 0-3 with a 5.94 ERA in seven starts before striking out eight and allowing three hits in seven innings of a 9-0 win over Miami on Thursday.
Bryce Harper is likely to be back in the lineup despite nursing a sore hip. He missed 13 games earlier this season due to a left knee injury, and he's batting .368 over the past 15.
"He keeps saying, 'I'm fine, I'm fine.' He's a tough kid," Johnson said. "That's the way he is."
Harper, 1 for 3 in the series opener, has a .352 career average in 14 visits to Citizens Bank Park.
The Phillies, who had four hits Monday's win, are slated to give Ethan Martin (2-3, 6.39) his first start against the Nationals.
The rookie right-hander gave up three runs with three walks and nine strikeouts in four innings of an 11-3 loss to the New York Mets on Thursday. That came five days after he didn't get a decision in his shortest outing of the season, surrendering three runs and three hits with three walks while getting pulled with two outs in the opening inning of a 12-7 loss to Arizona.
"I felt pretty decent almost every start," Martin told the team's official website. "Even (pitching coach Rich) Dubee said something. He said around that 60-pitch mark, I kind of have a little struggle in there. I've got to get through that. Hopefully, I can get to that point this year."
Martin is holding opponents to a .213 average the first time through the lineup, but they're hitting .328 with five doubles and six homers the rest of the way.
Updated September 3, 2013