Weaver looks to continue his mastery of Oakland on Sunday as the Angels try to avoid their first three-game skid since the beginning of the season.
The Angels (30-25) have mostly their pitching to blame for the losses in a 3-5 stretch, during which they own a 5.13 ERA. Starter Garrett Richards was blasted for five runs in just two-thirds of an inning in Friday's 9-5 loss.
Tyler Skaggs allowed four runs in six innings Saturday, but relievers Joe Smith and Michael Kohn were each charged with three runs in less than an inning. Oakland scored six runs in the seventh and four in the eighth in an 11-3 victory.
Los Angeles hasn't dropped three in a row since being swept at home by Seattle from March 31-April 2.
Weaver's performances against the Athletics over the last three years likely give the Angels some confidence. He's 8-1 with a 0.87 ERA in his last 11 matchups, including wins in four straight while surrendering one run over 29 2-3 innings. He threw a four-hit shutout in his last game in Oakland on Aug. 6, 2012.
The only Athletic hitting better than .235 in at least five at-bats against Weaver (6-3, 2.99 ERA) is Eric Sogard, who is 4 for 14. Josh Donaldson, whose 46 RBIs are tied with Brandon Moss for the team lead, is hitless in eight at-bats against Weaver.
The right-hander was less than stellar in a 6-4 win at Seattle on Tuesday, allowing three runs over six innings - the first time in eight starts he gave up more than two runs. However, he's still 6-1 with a 2.01 ERA over his last eight outings. That's the second-lowest ERA in the AL since April 18, trailing only Minnesota's Phil Hughes (1.94).
Yoenis Cespedes was a single shy of a cycle and matched a career high with five RBIs on Saturday to help Oakland (34-22) expand its division lead over the Angels to 3 1/2 games.
The A's will give the ball to Sonny Gray (5-1, 2.31), who didn't receive a decision after being charged with a season-high four runs along with eight hits over six innings of a 6-5 loss to Detroit on Tuesday.
"I've got to be a little bit better than that," said Gray, whose ERA trails only Masahiro Tanaka (2.06) of the New York Yankees in the AL.
Gray limited the Angels to a run on a Mike Trout homer over six innings but failed to get a decision in a 2-1 win Sept. 17 in his only start against them as a rookie. He also threw two scoreless innings of relief July 19.
Trout was a late scratch Saturday due to upper back stiffness, though manager Mike Scioscia told the team's official website he was hopeful Trout would be able to play Sunday. Trout's batting .415 with 10 RBIs during an 11-game hitting streak.
Moss likely won't play Sunday, Oakland manager Bob Melvin told the team's website, after he sat Saturday. Moss hit a grand slam Friday but later left with a tight right calf.
A's outfielder Josh Reddick left Saturday's game after hyperextending his knee while fielding a flyball and is day to day.