Whether or not baseball's best team will have one of its top hitters in the lineup Thursday remains to be seen.
Samardzija (1-1, 3.27 ERA) pitched well over seven innings Friday, but he gave up a pair of two-run homers before the A's rallied in the ninth for a 5-4 victory over Baltimore. It marked his third start with Oakland after he went 2-7 with a 2.83 ERA in 17 outings for the Chicago Cubs.
The right-hander has felt comfortable with the first-place A's (62-38) after being acquired with Jason Hammel in the July 4 trade.
"I just kind of wanted to make it as seamless as possible," Samardzija told MLB's official website. "They get to see how you play and how much it means to you to play this game. That puts us on common ground, because they're just a bunch of gamers and dirtballs who love to play."
Samardzija made three starts against Houston while he was with the Cubs, going 2-1 with a 2.70 ERA. He'll look to improve on those numbers in this contest, though Cespedes' status is unclear after he left Wednesday's 9-7 victory over Houston with a sprained right thumb.
Cespedes snapped a career worst-tying 25-game homerless drought by hitting two and tying his career high with five RBIs, but he had his hand examined after an awkward swing in the fifth inning. He was replaced in left field by Craig Gentry to start the seventh.
Manager Bob Melvin said Cespedes' X-rays were negative.
The Astros (42-59) have their own injured slugger, as rookie George Springer was placed on the 15-day disabled list with a strained left quad prior to Wednesday's contest. He's missed the last three games for Houston, which has dropped four of six.
Jon Singleton drove in two runs as the Astros made it close with a five-run eighth before having their three-game winning streak over the A's snapped.
Houston has lost seven of the last eight meetings in Oakland, where Scott Feldman has had some trouble in his career.
Feldman (4-7, 4.30) has gone 1-5 with a 10.24 ERA in six starts at O.co Coliseum, and he allowed eight runs in 1 2-3 innings while with Texas in his latest visit on June 4, 2012.
After a rough outing in a loss to Boston on July 11 before the All-Star break, the right-hander was solid Friday against the Chicago White Sox and gave up three runs in seven innings of a 3-2 loss.
It matched Feldman's longest start of the season, and he had a four-hit shutout going into the sixth before giving up a two-run homer. He hadn't pitched seven innings since doing so in back-to-back starts April 6 and 11.
''I think if you want to sit down and break down your outing, it's never perfect,'' Feldman said. ''I had my share of ones like (Friday) where I sort of got beat on one particularly bad pitch."
Former Astro Jed Lowrie, who homered Wednesday for the first time since June 1, is 4 for 9 with two doubles off Feldman and is hitting .375 during an eight-game hitting streak against Houston.