"I gave up three home runs, but I felt I was executing pitches pretty well," Griffin said. "It was just not our day. Weaver was on; he was really spotting up on that white line. It's just frustrating to me."
A's manager Bob Melvin said Cespedes was day to day.
"I wouldn't think so," Melvin said when asked if the wrist ailment was connected to Monday's Derby. "You would think he'd have felt it then, and he didn't. It came up today in batting practice. Before the game he was taking swings in the cage and still felt it."
The A's, who went to the All-Star break in first place for the first time since 1990, stalled coming out of the intermission but retained their two-game lead over the Rangers in the American League West.
Weaver, a 20-game winner in 2012, picked up his fourth win in nine decisions in an injury-plagued season, looking like the dominant ace he's been since 2010.
Weaver blanked the A's on four hits and four walks across 6 2/3 innings, striking out eight. He has a streak of 24 2/3 scoreless innings against Oakland and is 7-1 with a 0.84 ERA against the A's since 2011. He's 10-7 in 25 career starts against the AL West rival.
"I think that you match up well against certain teams, and Oakland is a team that I've had some success against," Weaver said. "But at the same time, they've done well against me."
Griffin (8-7) lasted five innings, giving up four runs on six hits and a walk with four strikeouts. Griffin has yielded a staff-high 21 homers in 127 1/3 innings. Sixteen of those 21 homers have been solo shots.
"It means he's trying to get ahead, throw strikes," Melvin said. "Guys who have good command tend to give up homers sometimes."
Pujols unloaded on a full-count slider, Aybar on a 2-2 fastball and Trout on a 2-1 changeup.
The A's, who got two hits from Eric Sogard, had runners in scoring position in the third and fifth innings but were frustrated by Weaver, with some help from his defense.
Over their past seven games, the A's have scored no more than three runs and are batting .167 with a total of 13 runs scored.
Chris Young made his presence felt in left field before most of the fans even knew he was in the game, having replaced Cespedes.
With runners on first and second in the bottom of the first, Pujols lashed a line drive seemingly headed for the left-field corner. But Young got a quick break on the ball and made a running catch.
Young's play looked even bigger one batter later when Josh Hamilton dropped an RBI double in front of a diving Josh Reddick in right field. But Griffin struck out Howie Kendrick and escaped when Josh Donaldson -- who'd made a throwing error on J.B. Shuck's leadoff hit -- made a sprawling stab at third and threw out Mark Trumbo to end the inning.
Griffin, who'd given up one earned run in 16 previous innings at Angel Stadium, sailed into the third when Pujols unloaded his 16th homer of the season and No. 491 of his career over the left-field fence.
The A's threatened in the top of the third, but a superb play by Alberto Callaspo at third snuffed a rally. Donaldson's bullet was smothered by Callaspo, who jumped to his feet and beat a diving Sogard at third in a bang-bang play disputed by Melvin. Sogard's double was the only extra-base hit allowed by Weaver.
"He's tough to pick up," said A's designated hitter Seth Smith, who was hitless with three strikeouts in four at-bats. "It never gets easy. You get to the point where you know what they look like, but you don't know where it's coming. It's the big leagues; there's no gimmick. It's all pitching. He keeps the ball out of the middle of the plate."
An opportunity got away from the A's in the fifth after Coco Crisp singled with one out and stole his 15th base. John Jaso drew his second walk of the game but was picked off at first by catcher Chris Iannetta, ending the threat.
"I don't know if I've ever been picked off in the big leagues," Jaso said. "I know I was getting too far off. I felt it and didn't do anything about it."
Aybar led off the bottom of the fifth with a homer, his fourth, inside the right-field foul pole. Two batters later, Trout joined the homer party with his 16th, to left-center.
Brandon Moss opened the ninth with a single to right-center, advanced to second when Hamilton misplayed the ball on a hop and scored when Young doubled, avoiding the shutout.
Sonny Gray held the Angels to one hit and a walk while striking out three in two innings. After two flawless performances, the hard-throwing right-hander with the big future is returning to Triple-A Sacramento to clear roster space for Dan Straily, the A's starter on Saturday night.