Weaver, who has been told to be ready to go on short rest if needed, did not get a decision on Friday against the New York Yankees, but was tremendous, as he allowed just a run and three hits and struck out 11 in eight innings of a 2-1 win.
"I felt great," Weaver said. "My location was a little better than the last couple of outings. The defense played great, and I was able to locate as well as I have all year."
The talented right-hander beat the A's the last time he faced them, but is 5-6 lifetime against them with a 3.00 ERA in 18 starts.
After losing Monday's opener, the Halos bounced back on Tuesday, as Howie Kendrick belted a pair of two-run homers, and the Angels turned four double plays in a 6-3 win. Maicer Izturis drove in the go-ahead run in the seventh inning for Los Angeles, which remained three games behind first-place Texas in the American League West.
Jerome Williams allowed seven hits and walked five batters over 4 1/3 innings in the start for the Angels. Hisanori Takahashi (4-3) pitched 1 2/3 frames to get the win and Jordan Walden retired the side in order in the ninth for his 30th save.
Guillermo Moscoso, who came within four outs of a no-hitter his last time out, was charged with five hits and three runs over 4 2/3 frames Tuesday. Fautino De Los Santos (2-2) suffered the loss.
Josh Willingham knocked in two runs for the A's, who lost for just the third time in their last 13 home games vs. the Angels.
"Guys that normally come through for us didn't," A's manager Bob Melvin said. "On top of that we hit into double plays. It was a rough night for us offensively when we had runners on."
Getting the call for the A's today will be righty Rich Harden, who is 4-2 with a 4.74 ERA. Harden did not get a decision last Monday against Kansas City, as he surrendered four runs and eight hits in five innings of an 11-6 loss.
Harden has faced the Angels 16 times (15 starts) and is 6-3 with a 3.77 ERA.
Despite Tuesday's loss the A's have been a thorn in the side of the Angels this season, taking nine of the 15 matchups, including six of the eight meetings in Oakland.