Washington went 4-3 on its recent homestand and kicks off a 10-game road trip with the trip to Houston. The Nats sit three games ahead of the Braves, who took two of three from the Astros at home this weekend.
Right-hander Edwin Jackson will start for the Nationals. He was decent in his last outing, giving up three runs in 5 2/3 innings against the Phillies. All three runs came on solo homers -- two by Jimmy Rollins.
"I just got hurt on balls up in the zone," Jackson said. "Got behind in some counts. Each time I made pitches when I needed to, I had some great defensive plays behind me. The three home runs -- three solo home runs -- I got hurt on, two of them were just up and one was middle in and he was waiting for it."
In his last six starts, Jackson is 2-3 with a 5.40 ERA. Opponents are batting .309 with seven homers off him during that stretch.
The Astros have spent most of the second half on the road, which hasn't been kind to them. They are 25-27 at home, but went 1-6 on their last homestand.
Left-hander Dallas Keuchel will get the ball in the opener. After posting a 1.35 ERA in his first three starts, Keuchel has a 10.42 ERA in his last four. He took the loss in all four outings.
He got hit hard in his last start, giving up seven runs on seven hits in four innings against the Brewers on Tuesday. He threw just 44 strikes in his 85 pitches, his lowest strike total of the season, and walked six.
"What was tough was Dallas' command," manager Brad Mills said. "He had six walks in those four innings and was working behind in the count. It's along the same lines as his last outing as well. It's something we're going to work on. We thought we had some things addressed, but we need to kind of go back and readdress those issues."
Astros: Maxwell swinging hot bat
Since an 0-for-5 night at the plate on July 16, outfielder Justin Maxwell is batting .346 in his last 52 at-bats. He's hit four homers over that span.
Maxwell certainly helped those numbers on Saturday, when he went 4-for-4 with two homers against the Braves. Against a right-handed pitcher on Sunday -- when Maxwell usually sits -- he was 2-for-4 with an RBI double. Manager Brad Mills said he thought Maxwell's stellar hitting on Saturday earned him another start.
This week, Maxwell will get a chance to face some of his former teammates from his six years with the Nationals' organization.
Catcher Jason Castro, out with right knee effusion since July 8, was set to catch five innings on Sunday night in a rehabilitation assignment at Double-A Corpus Christi.
Castro will move to Triple-A Oklahoma City on Monday. On Saturday with Corpus Christi, Castro went 1-for-2 and blocked a couple pitches behind the plate.
"He felt good. That's the biggest thing," Mills said. "Swelling and stuff was not an issue, so that was absolutely huge to be able to do that."
Nationals: LaRoche's strong season huge for lineup
Adam LaRoche, who missed most of last season with a shoulder injury, is batting .278 with 23 homers and 71 RBIs for Washington. The Nats looked to sign a first baseman in the offseason, but sticking with LaRoche, 32, proved to be a strong move.
"I think the older that I get, the more I learn about hitting. I still have a lot to learn, I have a long way to go," LaRoche said. "I think in the last few years, I've gotten a little wiser in some situations. Before, I was trying to do too much. I'm trying to be a little more consistent."
The Nationals have a club option with LaRoche for next season, but there haven't been contract talks quite yet, according to the first baseman.
With a single in the fifth Sunday, Michael Morse extended his hitting streak to 14 games. It's the second-longest current streak in the National League, behind Jose Reyes' 24, which he also kept alive in Sunday's game.
The Nats conclude a stretch of 35 games in 34 days with this 10-game road trip. They are 16-9.