A day after being shut out by lefty Jason Vargas, the A's managed just one run on five hits in seven innings against Weaver, who locked up the series win for Los Angeles in dealing Oakland a 3-1 loss.
The A's had totaled 49 runs over five games before these two losses, and it's the first time they've dropped two in a row in more than a month. They lost three straight beginning Aug. 20.
"That means we've been playing really well," manager Bob Melvin said. "We've faced some pretty good pitchers these last two days and offensively didn't do what we have been doing. It felt like we were a little bit tired these last couple of days, playing 33 of 34, and usually you don't want an off-day when you're playing well, but I think tomorrow could be a good time for one."
It'll come in Seattle, where the A's will finish out the regular season with three games against the Mariners, who have beaten the A's 10 times in their first 16 tries this season.
Oakland's latest deficit sets the club back two games behind the Red Sox for the best American League record, which would secure the top seed in the playoffs, and its lead over Detroit was cut to one after the Tigers beat the Twins, 1-0, to win the AL Central title. But should the A's be tied with the Tigers at the end of the regular season, Oakland owns the first tiebreaker.
Weaver faced just three over the minimum through the first five innings before snapping a 29 1/3 scoreless-innings streak against the A's in the sixth. Coco Crisp and Eric Sogard hit back-to-back singles, and Jed Lowrie followed with a sacrifice fly.
But that's all the A's could muster against the right-hander, who improved to 11-7 with a 2.23 ERA in 26 career starts against Oakland, including 5-0 with a 0.41 ERA in six outings since the start of 2012.
Weaver was pitching on nine days' rest, after missing his last start because of tightness in his right forearm, having already lost nearly two months of the season because of a broken left elbow -- one of many blows dealt to an Angels club that entered the season as a favorite to win the AL West.
"I don't know if Weave needs a pennant race to be motivated to pitch, but there's no doubt that our performance and not meeting expectations has been hard on everybody around here," Angels manager Mike Scioscia said. "I think Weave has expectations -- that's why he stayed here. He has expectations of us getting to the playoffs, getting championships and getting the World Series, and we've got a little work to do before we can get there, but I don't think there's any frustration in Jered. He'll go out there and pitch in any circumstance and give it all he has."
As was the case Tuesday night, this type of performance ruined a rather impressive one from Oakland's own starter. A.J. Griffin took the loss on Tuesday after allowing three runs through five innings, and Dan Straily was forced to do the same after giving up just as many on seven hits in 6 2/3 innings on Wednesday.
"I thought he threw the ball well again," Melvin said. "When you lose and don't score many runs, it looks like you got knicked up a little bit, and that's what happened with him. He gives up three runs, similar to A.J. last night, pitching well enough to keep your team in the game, but when you get shut out and score one run, it makes it look a little different."
"Obviously, it's not the end result we're all looking for, but there were a lot of good things, threw a lot of good pitches today," Straily said. "I threw a lot more changeups, a lot more curveballs than I had been, so I can take positives from that. I was getting ahead, getting guys in swing mode."
Only the Angels' fourth-inning run was earned. In the fifth, Straily issued a leadoff walk to Chris Iannetta, and first baseman Daric Barton dropped the throw from third baseman Alberto Callaspo on Andrew Romine's ensuing sacrifice bunt, putting runners on first and second for Collin Cowgill.
Cowgill, the former A's outfielder, placed down his own sacrifice bunt. Then J.B. Shuck hit a grounder to shortstop Lowrie, who threw home to nail Iannetta. But Erick Aybar came through with an RBI hit to keep the rally going and, after Straily walked Kole Calhoun, Josh Hamilton notched a run-scoring infield single.
Straily finishes his first full season with a 10-8 record and 3.96 ERA. It's unclear whether the A's will opt to use him or rookie Sonny Gray as their fourth starter in the AL Division Series, though Gray appears the front-runner.
Straily couldn't have left a better impression, though.
"I went out there and got my work in and was more effective and able to go deeper in the ballgame than I had the last couple of times, so that was good," he said. "I've had ups and downs like every other season, and I finish with a loss, but that's as close to a quality start as you can get, so I'll take it, but at the same time, I'm never satisfied with anything."