A look at what's happening around the majors Tuesday:ONE-TWO PUNCHHouston goes into a doubleheader against the Chicago White Sox with two of the pitchers the Astros hope will carry them deep into October. In the opener, Zack Greinke will make his second start for AL West-leading Houston since he was acquired from Arizona in a blockbuster trade at the deadline. Greinke is a combined 11-4 with a 3.08 ERA and got the win with a middling performance in his Astros debut, allowing five runs in six innings against the Colorado Rockies. Gerrit Cole (14-5, 2.87 ERA) has been an ace for the Astros all season and is among the favorites for the AL Cy Young Award. The last team to beat him was the White Sox — way back on May 22. The doubleheader was scheduled after Monday's Astros-White Sox matchup was postponed by rain.SCHERZER'S SIM GAMEWashington Nationals ace Max Scherzer is expected to throw a simulated game Tuesday as he tries to get closer to returning from a back muscle injury. Manager Dave Martinez said the team would see how the three-time Cy Young Award winner feels after that test before determining what comes next in Scherzer's recovery. Scherzer returned from a stint on the injured list in July but made just one start before being shelved again. "This is a progression thing; there is no timetable for him," Martinez said. "We just want to make sure when he comes back, he is 100 percent this time."BAY AREA BASHThe Oakland Athletics head across San Francisco Bay for a quick two-game series with their area rival, the Giants, as both teams chase wild card berths. The two-game set at Oracle Park ends an eight-game trip for Oakland that was short on travel. The A's spent an entire week in the same Chicago hotel as they played the Cubs and White Sox and then get to sleep in their own beds while facing the Giants. Oakland is 1½ games behind Tampa Bay for the second AL wild card spot, while San Francisco held onto ace Madison Bumgarner at the trade deadline as it makes a long-shot playoff push in manager Bruce Bochy's final season. Bumgarner (7-7, 3.74 ERA) starts Tuesday night against Oakland's Brett Anderson (10-7, 3.99).FREE FALLINGThe Minnesota Twins' lead in the AL Central over the Cleveland Indians is gone, and the struggles of left-hander Martín Pérez have been part of the problem. Pérez, who starts the opener of a two-game set at Milwaukee on Tuesday, has just one win since May 23 and has pitched to an 8.14 ERA in his past four starts, leading to speculation he may be moved back to the bullpen, where he began the season.SURGINGNew York Yankees right-hander Domingo Germán (15-2) tries to become the first 16-game winner in the major leagues when he starts against Baltimore and LHP John Means (8-7). Germán is 6-0 in seven starts since nearly a month on the injured list with a strained left hip flexor.___More AP MLB: https://apnews.com/MLB and https://twitter.com/AP_Sports