The Houston Astros' sluggish start has resulted in some changes, one of them netting Chris Devenski his first big-league start.

The Oakland Athletics have re-shaped their own rotation and will counter with another fresh face Saturday.

While Devenski hopes to lift the struggling Astros after another deflating loss in the opener, Jesse Hahn will try to give the Athletics their seventh win in the last eight meetings of this series in Oakland.

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Houston (7-16) seemed to finally have its first winning streak in hand with a 4-2 lead Friday entering the bottom of the eighth inning. Instead, the Athletics (12-12) rallied for a 7-4 victory, capped by Yonder Alonso's mammoth walk-off three-run homer with one out in the ninth.

Ken Giles, Tony Sipp and Pat Neshek combined to cough up five runs in the final two innings, leaving the Astros' bullpen with an AL-worst 4.94 ERA.

Houston's eighth loss in 10 games has it tied with Minnesota for the league's worst record. The Astros fell to 3-10 on the road, better than only the Twins' 1-10 mark.

"What's been consistent is every mistake we make has been magnified," manager A.J. Hinch said. "They come back to haunt us."

It was another shocking loss for the Astros, who led the AL with a 3.57 ERA a year ago on the way to their first postseason berth since 2005.

So far this season, Houston ranks dead last in the league with a 5.08 ERA - a 5.16 mark from its starters. While Lance McCullers is out with shoulder soreness, ace Dallas Keuchel and Collin McHugh have yet to duplicate their success from last season.

It will be up to a rookie to halt the downhill trend, which includes at least seven runs allowed in five of the last 10 games.

Devenski (0-0, 0.66 ERA) has been a lone bright spot out of the bullpen, holding opponents to 11 hits and one solo home run in 13 2/3 innings. The right-hander has walked just one batter while striking out a dozen.

He's switching roles at least for one turn in the rotation with the ineffective Scott Feldman and will face an Oakland lineup that had struggled mightily before breaking out late Friday night.

The Athletics had averaged 3.5 runs in their previous six games but used homers from Alonso, Marcus Semien and Coco Crisp to pull out their third straight home win after opening 1-7 at O.co Coliseum.

But while Alonso's late heroics served as a shot in the arm, Oakland is in need of some to fill its starting rotation.

After opening a season-high 10-game road trip with four straight wins, Oakland starters struggled to a 9.67 ERA while finishing the trip 1-5. The kicker was the news Chris Bassitt was headed to the 15-day disabled list with a right elbow strain.

Sean Manaea, Oakland's top pitching prospect, made his big league debut in Friday's opener of a six-game homestand, and it will be Hahn to follow.

The right-hander was called up from Triple-A Nashville, where he battled blister issues to go 0-1 with a 2.04 ERA. He went 6-6 with a 3.35 ERA in 16 starts with Oakland last season before a forearm injury ended his second big league season.

Hahn didn't make a roster spot after a flat spring in which he had a 11.15 ERA and .382 opponents average.

"I was pretty motivated," he told MLB's official website. "I just wanted to make it a short stay and do everything I needed to do to get back up here as quick as possible."