Bud Norris (4-1, 3.58 ERA) will start for the Astros, and the right-hander has had three great starts in a row, with a 0.47 ERA in May.
It's the best ERA in the Major Leagues this month for pitchers with at least three starts, and the Astros are 7-1 in Norris' starts this season.
Meanwhile, the Cubs have been struggling to score runs.
They hit .277 with 21 extra-base hits and 29 runs on a five-game road trip, then hit .214 (34-for-159) with 13 extra-base hits and 15 runs scored in five games of a homestand that ended Sunday with a 6-0 loss to the White Sox at Wrigley Field.
"Our offense has to step up, there's no getting around it," Cubs Manager Dale Sveum said. "We have to step up to get three-run innings, multiple crooked numbers all the time, as much as you possibly can.
"It's too difficult to not do anything off starting pitchers and think you're going to do stuff off the back end of bullpens."
Sveum was asked if he would like to see more patient at-bats by his hitters.
"In a long-term basis, you're always trying to get on-base percentage. You've got to get guys on base, and then obviously have the guys who can hit the ball out of the ballpark and sustain innings follow," Sveum said. "You've got to keep the line moving somehow, and you do that through walks and pitch selection as much as anything."
Norris, the Astros' 27-year-old right-hander, gave up four hits and one earned run while striking out nine in his last start, an 8-3 win over the Brewers on Wednesday.
Norris just wants to keep the ball rolling.
"Just gotta keep going back out there," he said. "I've been throwing the ball really well. Just keep my routine."
Norris wants to continue to limit his walks.
"That's something that's just going to help you manage the game," he said. "Walks are never going to help you in that regard. Sometimes you got to pitch around some guys in certain scenarios, but for the most part, attack hitters with your best stuff and try to get outs."
Cubs: Garza gets the start
Matt Garza (2-1, 2.58 ERA) will make his eighth start of the season on Monday. Garza is 1-1 with a 3.71 ERA in his three road starts this season.
In his last start, a no-decision against the Phillies on Wednesday, Garza pitched 6 2/3 innings, allowing two runs on eight hits.
Astros: Schafer might be back Wednesday
Houston center fielder Jordan Schafer is recovering after injuring his leg avoiding a collision in center field on Saturday. Manager Brad Mills said Schafer has a muscle strain in his lower right leg, and expects him to return by Wednesday.
In the last two seasons, left-handed batters have three hits in 51 at-bats (.059) against Astros left-handed reliever Wesley Wright.