OAKLAND -- If the Yankees are wondering whether J.A. Happ is worthy of consideration for their postseason starting rotation, the answer may have continued to materialize in their 6-4 loss Wednesday night to the Oakland A’s.

• Box score

Happ lasted three batters into the fifth inning, departing with the bases loaded and nobody out. He allowed five runs in four-plus innings, hiking his ERA in his last six assignments to 8.07. The Yankees generated some late offense but lost their third game in a row to drop their still-impressive overall record to 83-45.

What confounds the Yankees is that Happ (10-8) appears to possess decent stuff. Yet he has allowed 31 homers, ranking him among the American League’s most frequent victims of power.

“I’m struggling to keep the ball in the park,” Happ said. “We’re trying to do everything we can between starts to try to figure out sequencing, location, execution, delivery.”

Yankees manager Aaron Boone, who insisted that Happ will make his next start, suggested that the left-hander might try supplementing his fastball by resorting more often to his changeup and slider-cutter combination.

“The stuff is there enough for him to go out and continue to be successful,” Boone said. “We have to continue to find a way with him … build on a lot of the positive things that are happening.”

Boone said that the pair of two-run homers that Happ yielded fit the pattern of his persistent lapses.

With two outs in the second, Happ was on the brink of throwing his second consecutive perfect inning. Then Stephen Piscotty singled to prolong the inning. Up came Khris Davis, who belted his 18th homer of the season.

Boone pointed out that Piscotty got enough wood on a changeup to register his hit. Then he missed over the plate with a fastball to Davis. Boone maintained that such errors in location, when committed by Happ, often wind up as home runs. Rarely, said Boone, has a hitter proven mortal by singling or popping up.

In the third, Happ walked Josh Phegley on another close 3-2 pitch. Again Happ committed a location mistake, surrendering a home run, this one by Marcus Semien.

“The velocity and the life on the fastball were there,” Boone said.

For the second night in a row, the Yankees out-hit Oakland, this time 11-6. New York went 3-for-9 with runners in scoring position but still left 10 runners aboard.

“A lot of good at-bats,” Boone said. “We couldn’t quite break through again to make it a real dynamic offensive night.”

The Yankees brought the potential go-ahead run to the plate in the eighth inning, but A’s relief ace Liam Hendriks struck out Aaron Judge to strand runners at the corners before completing a five-out save.

Hendriks was asked whether he was motivated more than usual facing Judge, who homered off him in last year's American League Wild Card Game.

"Not really," Hendriks said. "You know who he is and what he’s been able to do, but it’s still a guy with a bat. My job is to get him out. I try not to look too much at who’s up, because that can get me into trouble.”