Shortstop Cristian Guzman was the only one to post solid numbers in the leadoff spot, going 17-for-56 (.304), but he is out for the season because of a left thumb injury.
On Wednesday, manager Manny Acta went back to the drawing board and put shortstop Felipe Lopez back in the top spot. Lopez, who was batting seventh in the order, was 1-for-13 (.077) in his last four games, entering the finale against the Astros, after going 8-for-17 in his previous five.
"It's good to be leading off. It means that I get more at-bats," Lopez said. "I feel like I've been putting together some good at-bats lately. That's where I belong."
Lopez ended up going 1-for-5 on Wednesday.
Acta said he and Lopez had a talk recently, and both agreed that the shortstop was ready to go back to the leadoff spot. The move also means that when he is activated from the disabled list, outfielder Alex Escobar will most likely hit seventh in the order.
"He has had some better at-bats," Acta said of Lopez. "He feels he is ready to do it. All along, I felt [Lopez] was the ideal guy to lead off for us. Obviously, the guys we have tried there [except for Guzman] haven't set themselves apart."
Lopez didn't do so well the last time he was at the top spot, hitting .231 with a .277 on-base percentage. Asked what he has to do differently to become a better leadoff hitter, Lopez said, "It's nothing different, just get on base. [Ronnie] Belliard and [Ryan] Zimmerman are hot, so maybe I will see more fastballs, maybe not. I have to take advantage of it."
The word on Zim: In the bottom of the ninth inning Wednesday, Zimmerman suffered a bruised right wrist trying to field a ground ball off the bat of Astros second baseman Chris Burke. Zimmerman still tried to throw Burke out, but his throw went past first baseman Robert Fick for an error.
Acta and assistant athletic trainer Michael McGowan then came to Zimmerman's aid, but the third baseman remained in the game.
"He has the seams of a baseball mark there," Acta said of Zimmerman's injury. "He got hit pretty hard, but he is a tough kid and he doesn't think it's going to affect him going forward."
He knows the score: Outfielder Ryan Langerhans ended up driving in the game-winning run Wednesday, when he hit a three-run home run in the bottom of the fifth inning off Astros right-hander Jason Jennings. The hit came on the first pitch.
"I swung at some bad pitches my first two at-bats, and [hitting coach] Lenny Harris told me to be patient and wait for something good. I hit the first pitch. I guess I wasn't exactly patient, but it was right there and I put a pretty good swing on it."
As a member of the Nationals, Langerhans is hitting .205 with five home runs and 18 RBIs. And with Escobar coming back soon, the Nationals have to make a decision on who to keep between Langerhans and Nook Logan. Acta has not ruled out an infielder leaving the 25-man roster.
Langerhans said he tries not to think about the decisions the Nationals have to make.
"All anybody can do is go out and play and let that stuff take care of itself," Langerhans said. "Those guys [management] make those decisions."
What a relief it is: Saul Rivera has been the workhorse for the Nationals this season. Despite starting the season in the Minor Leagues, Rivera ranks third in the Majors in appearances with 48.
Rivera been involved in just about every role out of the bullpen, from long reliever to setup man to closer. In fact, he has three saves this season. Rivera's success on the mound has allowed the Nationals to be careful with Luis Ayala, who is coming back from elbow reconstruction surgery.
"I really don't know where we would be without Saul, because he has been huge," Acta said. "He has given us so many quality innings. Saul is a guy I'm not afraid to put him in the fifth or to close a game, when [Chad] Cordero and [Jon] Rauch are not available."
Injury report: Left-hander Micah Bowie (left hip) continues to improve. He played long toss and did well in his agility drills on Wednesday morning. He said he hopes to have a bullpen session sometime this weekend.
Stat of the day: In the last 52 games, Dmitri Young is 79-for-194 (.407).
Did you know? The last Washington-based player to win a batting title was Mickey Vernon of the Washington Senators. In 1953, he won the American League batting title with a .337 average.
Coming up: The Nationals remain at Robert F. Kennedy Stadium and open a four-game series against the Rockies on Thursday night at 7:05 p.m. ET. Last year, the Rockies swept the eight-game season series against the Nats. In Game 1, left-hander Matt Chico will face Colorado right-hander Ubaldo Jimenez.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.