OAKLAND – A bad bounce. A couple of bad calls, at least in Boston’s initial point of view. That’s what left a bad taste in the Red Sox’ mouths as they suffered a 3-2 loss to the Oakland Athletics at McAfee Coliseum last night.

Throw in a bad travel schedule, and suddenly the Red Sox are looking more mortal than they did a week or so ago, not to mention a tad frustrated. That frustration led to a pair of spirited arguments last night with plate umpire Dan Iassogna, who ejected Boston manager Terry Francona in the eighth.

Last night’s setback extended Boston’s season-worst losing streak to four games, and to six losses in the last seven games overall. The Red Sox still lead the American League East by nine games over Toronto, but they haven’t been able to stay out of double plays in Oakland, nor have they been able to catch many breaks.

“We ain’t going to be hitting on all cylinders all year. If we did, we’d be the first team in history to do that,” said closer Jonathan Papelbon, who has had only three save chances since May 6.

Designated hitter David Ortiz says he thinks at least part of the reason for the skid can be traced back to the team’s difficult travel schedule.

Boston and New York played a typically intense three-game set at Fenway Park last weekend. That series culminated in a four-hour game on national television Sunday night (the Sox lost), ending a little after midnight and immediately followed by a cross-country flight and a 5:30 a.m. check-in time in their San Francisco hotel on Monday.

Boston has dropped three in a row in Oakland since, scoring only six runs in 29 innings, including a 5-4, 11-inning loss on Monday night.

“It seems like everything changed after the travel we had to do (to get) here,” said Ortiz. “The intensity. The little stuff. It’s not there. It’s a different feeling. We don’t have the intensity we normally have. That’s my view. A lot of guys are trying, but it’s not coming together. We have to come back and figure it out.”

Kevin Youkilis, who could only watch helplessly as Eric Chavez’s routine bouncer in the fourth kicked off the first-base bag and bounced over his head, sparking Oakland’s three-run flurry against starter Tim Wakefield, agreed that the difficult travel hasn’t done this team any favors. But it’s not the only reason for the slide.

“I’m not saying that’s the reason we haven’t played well. We haven’t hit well. We haven’t played well. The ball hasn’t hopped our way the last couple of days. West Coast. East Coast. We have to hit and play better baseball,” he said.

The Sox’ frustrations began piling up in the early going, when Boston hitters kept banging into double plays. Chavez, the Athletics’ third baseman, started double plays in the second, fourth and fifth innings, backing a solid start by left-hander Joe Kennedy (seven innings, two runs).

That made it seven double plays grounded into by the Red Sox in a two-game stretch, and eight double plays overall, including a soft liner by Ortiz that was turned into a twin killing on Tuesday night.

“Some of it is, they’ve been making (good) pitches in certain counts, and sometimes we’ve gotten a little anxious and roller over,” said Francona, trying to explain the rash of DPs. “They are making (good) pitches and that has kept them out of trouble.”

Wakefield, meanwhile, was in trouble in only one inning, the fourth. The knuckleballer, who had been 1-3 with a 9.13 earned-run average in his previous four starts, worked 6 2/3 innings last night.

He was matching Kennedy zero for zero until the fourth, when Chavez’s bouncer, which seemed to be an easy out, hit the bag and jumped into right field for a double. Instead of two outs and nobody on, Chavez was at second with one out.

Chavez went to third on a wild pitch, but stayed there on Dan Johnson’s bouncer to a drawn-in second baseman Dustin Pedroia. But Jack Cust ripped an RBI double to right, and Bobby Crosby rifled a 1-and-2 pitch to left-center for a two-run single and a 3-0 Oakland lead.

Wakefield would have liked the Crosby pitch back.

“I tried to throw a hard (knuckler) and bury it into the dirt, but it stayed up. That one pitch cost us the game,” said Wakefield, whose record fell to 5-7 despite making mechanical adjustments that made his signature pitch much more effective last night.

The Sox rallied after the first confrontation with Iassogna. Ortiz went ballistic when Iassogna called him out after he thought he had checked his swing on a 3-and-2 pitch with two outs and no one on in the sixth.

In the next inning, a double by Manny Ramirez, a triple by Youkilis and a groundout by Wily Mo Pena produced two runs, cutting Boston’s deficit to 3-2.

But three relievers, the last of whom was Santaigo Casilla (first career) save, preserved that lead for Kennedy. Pinch hitter Jason Varitek flied to center on the first pitch he saw after Casilla issued a two-out walk to pinch hitter J.D. Drew, sealing the Sox’ fate, with Francona watching the final outs on TV.

Francona said, after watching the replay, that maybe the pitch to Dustin Pedroia he objected to in the eighth wasn’t so bad at all. That, though, had nothing to do with the outcome, which once again was a tough one for the Sox to swallow.

skrasner@projo.com