Oakland is a team in flux, with Scott Kazmir departing for Houston last week and Tyler Clippard poised to be the next pending free-agent-to-be moved.

There were strong indications after the A’s 4-3 loss at AT&T Park on Sunday that Clippard could be heading elsewhere, perhaps as soon as Monday. The Nationals, Mets and Yankees are all possibilities, according to sources. Clippard came up with the Yankees and spent most of his career pitching for Washington.

Ben Zobrist, the A’s utilityman who went 6-for-11 in the three losses to the Giants, also is expected to be traded this week, with the Nationals, Cubs and Royals among the many teams interested.

Oakland has lost four in a row since Kazmir was traded to the Astros.

“We ran into a really good team at a tough time for our team,” Oakland catcher Stephen Vogt said. “They’re hot and playing as good as they’ve played all year, and it’s been a pretty crazy four days for us. Obviously now, there’s more looming and we know that. Definitely dropping these four made that more so.”

On Sunday, rookie Kendall Graveman had his second consecutive rough outing. Graveman, 24, lasted just 11/3 innings, faced 13 batters and allowed seven hits and two walks. He gave up all four of the Giants’ runs and was lifted after throwing 50 pitches, just 26 strikes.

“He fell behind hitters and when he needed to make a pitch in the zone, he was just up,” Vogt said.

“I’ve got to do better job of getting outs, getting deep into ballgames,” Graveman said. “Even behind in the count, I’ve got to throw quality pitches.”

Graveman has hit another trough, much like the one he was in to start the season. The right-hander, obtained in the Josh Donaldson deal with the Blue Jays, had an 8.27 ERA in April and was sent down to Triple-A Nashville. When he returned, he put up an ERA of 2.64 over his first nine starts, giving up no more than three runs in any of them.

But after back-to-back outings in which Graveman went seven innings and was unscored upon, he has stumbled again. Over his past three starts, Graveman has allowed 14 runs. In those 121/3 innings, opponents have recorded 17 hits and eight walks.

“He’s a rookie still, we’ve all be through it,” left-hander Drew Pomeranz said. “He’s a good pitcher and when he’s on, he’s on. He’ll be fine.”

Speaking of in flux, Pomeranz was scheduled to start Wednesday at Los Angeles, but he threw 33 pitches in relief Sunday and now Jesse Chavez will start against the Dodgers, on normal rest, thanks to Monday’s day off. Manager Bob Melvin said it hasn’t been decided whether Pomeranz will stay in the bullpen or return to the rotation. Pomeranz said, “I don’t care. I like to be in the big leagues, that’s as simple as I keep it.”

Assuming Clippard is traded, then Pomeranz is a candidate to become the closer.

Barry Zito coming up at some point soon isn’t out of the question, especially with Pomeranz’s role up in the air, Graveman’s recent dip and with Chavez having some struggles. Zito is scheduled to start Monday for Triple-A Nashville.

The bullpen was nails Sunday. Dan Otero replaced Graveman and got an inning-ending double play. Evan Scribner, trying to regain his form of early this season, worked two scoreless innings and turned in the snazziest play of the day, making a behind-the-back grab of a bouncer up the middle by Matt Duffy in the fourth.

The A’s did make another error (Brett Lawrie), their major-league-high 86th of the season, but the biggest mistake of the game came when, with one out in the ninth and Oakland down a run, Jake Smolinski broke from second and was thrown out at third trying to steal. It was a miscommunication: He was supposed to steal, but immediately. He thought it was a hit-and-run, and waited, then went late.

Marcus Semien then struck out to end the game.

Susan Slusser is a San Francisco Chronicle staff writer. E-mail: sslusser@sfchronicle.com Twitter: @susanslusser