Keuchel looks to build on his first win Thursday night as he tries to help the Astros win a third straight over the San Diego Padres in the finale of this four-game set at Minute Maid Park.Promoted from Triple-A Oklahoma City to replace the injured Bud Norris, Keuchel (1-0, 1.29 ERA) allowed a run and walked four in five innings of a 9-3 loss at Texas on June 17 in his major league debut. On Saturday, he yielded only a home run, one walk and five other hits in an 8-1 victory over Cleveland to record the first complete game by a Houston rookie since Taylor Buchholz on May 21, 2006."I'm so proud of Dallas being able to come in here and do that," manager Brad Mills said. "He's pitched extremely well both outings. I thought he mixed his pitches, got behind in the count, and was able to come back."Though it's only two starts into the left-hander's career, Mills might have a tough decision to make when Norris is expected to return to the rotation Friday at Chicago."That's what you want guys to do. You want to make those decisions difficult," Mills said. "We're going to think about some things and go from there."Keuchel has a tough act to follow after Lucas Harrell struck out seven and overcame four walks while tossing a six-hitter in Wednesday's 1-0 win over San Diego. Matt Downs' third-inning homer was one of two hits for the Astros (32-43), who have won four of five after losing eight of the previous 10 contests.J.D. Martinez had the other hit and threw out a runner at the plate in the ninth. He's 6 for 19 with three homers and eight RBIs in the last five games.Batting .177, Downs was starting in place of second baseman Jose Altuve, who has missed the last three games with a strained hamstring.It's likely San Diego's Andrew Cashner (3-3, 3.81) will not have to face Altuve when he returns from Double-A San Antonio to make his third major league start.The right-hander made his first 27 appearances out of the bullpen this season for San Diego before he allowed a run, two hits and struck out five in 2 1/3 innings of a 5-2 win at Milwaukee on June 9. The club then decided to send Cashner to the minors to get more work as a starter.In three starts at Double-A, Cashner went 2-0 with a 1.88 ERA, striking out 23 in 14 1/3 innings."We like the way he's thrown, he feels good," manager Bud Black told the Padres' official website. "He's followed the path that we've set out ... the report from our Double-A staff was good, they've seen the progress in stamina and endurance."Cashner, who was born just north of Houston in Conroe, is 2-1 with a 5.79 ERA in eight relief appearances against the Astros.Yonder Alonso and Logan Forsythe each had two hits Wednesday for the Padres (27-49), who left the bases loaded in the ninth and were shut out for the seventh time in 2012.Forsythe is 7 for 21 in his last five games since seeing regular time at second base.