PHOENIX -- The A’s came into Saturday’s matinee at Chase Field looking to build some momentum after snapping a five-game losing streak with a win over the D-backs in Friday night’s series opener.

Zac Gallen had other ideas.

The D-backs' ace returned from the injured list to hold the A’s to one hit -- a Brent Rooker broken-bat single in the first inning -- and one walk in six innings in Oakland's 3-0 loss.

"Anytime you run up against Gallen, you’d like to get the pitch count up, but he throws strikes and uses all four pitches,” manager Mark Kotsay said. "He got seven strikeouts today in the six innings he pitched, so effective."

The A’s stood at 17-17 on May 4, 1 1/2 games out of first in the AL West, but they’ve gone a Major League worst 13-38 since and are a season-high 17 1/2 games back following Saturday's defeat (pending Seattle's contest against Minnesota). They’ve won consecutive games just once (June 18-19 vs. the Royals) since winning six straight from April 28-May 4, and their last 19 days have been spent in the cellar.

One bright spot during this stretch has been Hogan Harris.

The lefty entered Saturday with a 2.28 ERA in five starts since joining the rotation on May 30, but that run of success hit a bit of a speed bump against the D-backs. The 27-year-old held them to three runs, but he allowed 10 hits and one walk in 3 1/3 innings -- his shortest outing as a starter so far -- and had to deal with traffic all afternoon.

“A lot of times I felt like I made a pretty decent pitch and they ended up getting hit just hard enough, whether it be right in the hole or blooping over people,” Harris said. “But the bright side of it is we still limited them [to three runs] -- and the fact that at least in the end you’re not walking people and forcing them to hit the ball.”

Right-hander Osvaldo Bido took over for Harris in the fourth inning with runners on second and third, one out and the A’s trailing 3-0. Kotsay opted to intentionally walk Christian Walker to set up the force and Bido made the move pay off, getting Randal Grichuk to ground into an inning-ending double play.

"I told Bido my favorite out he got was that double play in the fourth, of course,” Harris said. “He came out and did great. He’s got great stuff, man."

Bido ended up turning in 4 2/3 scoreless innings, so the game was still in reach after Gallen exited. Despite working on a one-hit shutout and having retired 14 A’s in a row, Gallen was done after six innings and 77 pitches in his first game back from the right hamstring strain that put him on the shelf on May 31.

Unfortunately for the A’s, there wasn’t any letup from the D-backs’ bullpen, with Kevin Ginkel taking the seventh and eighth innings ahead of closer Paul Sewald.

"I love what Bido did,” Kotsay said. “He came in in a tough spot there, got a double-play ball and put up zeros. He gave us a chance offensively to stay in the game or come back, and we’ve done that in the past, but today the arms [we faced] were really good."

Miguel Andujar singled off Ginkel to open the seventh and soon became the first A’s baserunner to reach scoring position, but he was stranded at second and Oakland went down in order in the eighth and ninth.

"[If] you don’t score, you don’t win,” Kotsay said. “That basically sums up the game.”