Weaver (7-1) who had been out with a lower-back strain he suffered in the first inning of the Angels' May 28 contest against the New York Yankees, allowed two hits, walked a pair and fanned three, but was removed after throwing 78 pitches.
"Weav does what he usually does, he located his fastball early," Angels manager Mike Scioscia said. "I really liked his fastball command. He changed speeds, a great effort."
Weaver moved to 5-0 at home this year, where his ERA stands at 0.70 in six starts. He also has won seven straight interleague starts and has an all-time such mark of 12-3.
"It felt great, it was nice to get back out there," Weaver said. "I wanted to establish my fastball command and keep them off-balance."
Ryan Vogelsong (6-3), who had six wins without a loss in an eight-start span, had that streak broken despite yielding seven hits and three runs while fanning six over seven innings.
"Weaver comes off the DL and he didn't miss a beat," Giants manager Bruce Bochy said. "We didn't put any pressure on him. A good outing by Vogy, he pitched well, we just couldn't do anything offensively."
The Giants, who didn't record an extra-base hit, lost to the Angels for the sixth time in the last seven meetings.
Callaspo homered to right in the second and it became 2-0 in the fifth on RBI singles from Erick Aybar and Mike Trout. Aybar's hit, which plated Howie Kendrick, glanced off the tip of the glove of a diving Brandon Crawford at shortstop. Buster Posey couldn't handle the one-hop throw to the plate from Melky Cabrera.
Morales, who came into Wednesday mired in a 1-for-19 slump, got hold of a Shane Loux pitch and homered to right-center leading off the eighth. Trumbo then cranked his 17th homer, a blast to left-center. Bobby Wilson doubled to the gap in right-center to score Kendrick later in the frame.
The Angels also placed pitcher Jerome Williams on the 15-day DL due to breathing problems...Vogelsong suffered his first road loss since Aug. 19, 2011 at Houston...Before Wednesday, the Giants had won each of Vogelsong's last eight starts...Trumbo had seven RBI in the series...It was the Angels' 10th shutout of the year, which tops the majors.
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