Texas has dropped five of its last seven games and 10 of 14 overall, including Sunday's 5-2 loss to the Boston Red Sox in Arlington.
Robbie Ross gave up five earned runs in 6 2/3 innings to fall to 1-4 with a 5.04 ERA on the season. It marked his fifth straight start without a win, while the Rangers have not won a series at home in three weeks.
"We're just not hitting on all cylinders," manager Ron Washington said. "We're not pitching at the same time. We're certainly not as consistent as we're capable of being on the offensive side; That's the way baseball flows."
The Astros have lost seven of nine, but they managed to avoid a three-game sweep at Baltimore over the weekend by winning Sunday's finale, 5-2. Jason Castro and Marc Krauss both went deep to help Houston rebound from Saturday's 5-4 loss in extra innings.
"We've played some good baseball the last two days," said Matt Dominguez. "Pitched the ball well, got some timely hits. Hopefully that can give us a jump start."
Still, the Astros entered Monday with the worst team batting average (.222) and the fewest runs scored (132) in the American League. They are also hitting a major league-worst .188 with two outs.
Houston will turn to Brad Peacock for Monday's series opener. After beginning the year in the bullpen, Peacock was moved into the rotation last month and has posted a 3.97 ERA in four starts, although he is 0-2 in that span.
He lasted a season-long 6 2/3 innings at Detroit on Wednesday but came away with the loss as he allowed three runs. Walks have been a problem for Peacock, who is yielding an average of 6.7 per nine innings. He issued four free passes against the Tigers.
For Texas, Colby Lewis takes the hill after getting tagged for seven runs in only 3 2/3 innings against Colorado on Wednesday. He gave up a career worst- tying 12 hits -- eight of which came with two outs -- as the Rangers went on to lose, 9-2.
Opponents are now hitting .355 against Lewis this season, although he has gone 4-1 with a 1.72 ERA in 10 career games against the Astros (six starts).
The Rangers went 17-2 against the Astros last season, and they won two out of three when these teams met in Arlington last month.