The injury bug has hit at the worst time of the year for the Oakland Athletics, who begin a seven-game road trip Monday against the Houston Astros. Closer Sean Doolittle was placed on the 15-day disabled list with a strained right intercostal muscle Sunday, when the Athletics lost for the ninth time in their last 13 games and fell one game behind the Los Angeles Angels in the American League West. Oakland is also without catcher John Jaso, who will be placed on the seven-day concussion list on Monday and replaced by Geovany Soto, who was acquired from Texas on Sunday. Second baseman Jose Altuve leads the majors with a career-high 178 hits for Houston, which has been held to three earned runs over their last four games. The Astros finished their 10-game road trip at 5-5 after losing 3-1 to Cleveland on Sunday, but outfielder Jake Marisnick continues to impress with six hits in his last four games. While Marisnick enters the series on a hot streak, Oakland first baseman/outfielder Brandon Moss is mired in an 0-for-18 slump while striking out 26 times in 57 at-bats this month.TV: 8:10 p.m. ET, CSN California (Oakland), CSN HoustonPITCHING MATCHUP: Athletics RH Jeff Samardzija (5-10, 3.27 ERA) vs. Astros RH Scott Feldman (7-9, 4.37)After posting a 2.70 ERA in his first four starts with Oakland, Samardzija has gone 1-2 with a 5.46 ERA over his last five outings. The 29-year-old is hoping to bounce back from a dismal outing Wednesday, when he allowed seven runs on seven hits in 3 2/3 innings against the Mets. Samardzija is 5-2 with a 3.48 ERA in 20 career games (five starts) against Houston, including two starts last month.Feldman held the Yankees to two runs over 6 2/3 innings on 121 pitches Wednesday to win for the third time in his last four starts. The Astros' opening day starter was pummeled by the Athletics on July 24 before holding them to one run over seven innings in his next start. Derek Norris is 5-for-7 and Josh Reddick has homered twice in 15 at-bats against Feldman, who is 5-7 with a 5.97 ERA in 24 career games (15 starts) against Oakland. WALK-OFFS1. Oakland CF Sam Fuld suffered a sore left knee in Sunday's game and is listed as day-to-day. 2. The Astros are 5-3 in their last eight games against the Athletics.3. Oakland is 49-12 when scoring first. PREDICTION: Athletics 5, Astros 3