HOUSTON -- Before dropping the series opener against the Houston Astros on Monday night, the Oakland Athletics had caught a glimmer of hope with consecutive series victories over postseason contenders Cleveland and St. Louis.

Oakland (57-74) has been besieged by injuries, using the disabled list a club-record 27 times this season. With starters Sonny Gray (strained right forearm) and Jesse Hahn (strained right shoulder) currently on the DL, the Athletics have been forced to fill the void with relievers making spot starts. At this point, the objective is a murky blend of pursuing wins while also evaluating young talent.

"That's the tough balance," Athletics manager Bob Melvin said. "A team that's in our position, we're trying to look at younger players as well as try to keep our veteran guys in the lineup enough to keep them happy too. It's not an enviable position to be in and we've put ourselves in this position with our record. It's a little bit of a delicate balance."

Right-hander Kendall Graveman (10-8, 3.97 ERA) will start for the Athletics on Tuesday looking to maintain his streak of exceptional appearances. Graveman is 3-1 with a 1.88 ERA in his last four starts and 9-2 with a 3.33 ERA in his last 16.

Graveman is 3-1 with a 4.60 ERA in his career against Houston, including back-to-back starts in July where he allowed four earned runs in 15 innings in two wins.

The Astros (69-62) welcomed back a critical cog in the bullpen on Monday night when veteran right-hander Luke Gregerson relieved rookie right-hander Joe Musgrove with one out in the sixth inning and runners on the corners in a 2-0 game.

Gregerson made his first appearance in 11 days after being sidelined with a left ankle injury suffered when he stepped on a sprinkler head in Baltimore. Gregerson has served effectively in a setup capacity since losing his job as closer earlier this season, and while the Astros have won eight of 10 games, his steady hand was missed.

Against the Athletics, Gregerson did his job with aplomb, inducing Yonder Alonso to hit grounder back to the mound that Gregerson turned into an inning-ending double play.

"I didn't know when the ideal spot to bring him in was, but I trust him with the ball in his hand as much as anybody," Astros manager A.J. Hinch said. "I don't care that he hadn't pitched in a couple weeks. He knows how to navigate innings. And that spot, highest leverage, big spot, we needed him to come in."

The Astros extended their lead in the bottom half of the inning and were able to complete the win without using right-handers Will Harris and Ken Giles. Both will be available when Houston attempts to claim the series on Tuesday night behind right-hander Collin McHugh (8-10, 5.01 ERA).

McHugh is 4-1 with a 3.40 ERA in his career against the Athletics, getting 47 strikeouts in 45 innings and seven starts. He has scuffled against Oakland this season, however, totaling just 11 1/3 innings in two starts with a 5.56 ERA. McHugh did not factor into the decision in either appearance.