Stephen Vogt and Marcus Semien homered off Shoemaker in the Athletics' 6-3 victory in Monday night in the opener of a four-game series, and Oakland reliever Dan Otero extended his scoreless streak against the Halos to 19 2-3 innings spanning 13 career appearances.
Shoemaker (2-1) was charged with five runs and seven hits while retiring only eight of the 18 batters he faced. The right-hander had won his previous nine decisions, beginning with a three-inning relief stint against Boston in a 19-inning, 5-4 victory last Aug. 9.
"There's not really much to explain, other than it was just one of those off-nights," Shoemaker said. "My stuff wasn't really working out for the best. I just tried to battle through some things, battle myself and try to execute pitches. I just chalk it up as one of those bad days, move on from there and get better."
Vogt, batting third in the order for the first time this season after hitting in the second, sixth and seventh spots, gave the Athletics a 4-2 lead in the third with his fourth homer, driving an 0-2 pitch deep into the right-field seats after a leadoff double by Sam Fuld and an infield hit by Mark Canha.
"I've hit in every spot in the order except leadoff since I've been here with the A's," Vogt said. "And what I'm learning is that it doesn't matter where you're hitting in the order. You take care of your at-bat the same way you would in every other spot in the lineup, because we jumble things so often here."
The Angels scored an unearned run in the bottom half when Albert Pujols hit the ball to left field over Canha's head, after Mike Trout reached on Semien's fielding error at shortstop and stole second. Semien, the Athletics' No. 9 hitter, got that run back in the fourth with a towering drive into the lower seats in the left-field corner on Shoemaker's 68th and final pitch.
It was the second time in three starts this season that Shoemaker surrendered a pair of homers — something that happened to him only once in his 21 previous big league starts.
"Matty was out of synch from the beginning. When he got 0-2 to Vogt, he left a split right over the plate," manager Mike Scioscia said. "He never settled in to what he does best — that's strike one, pound the zone, and change speeds. We'll turn the page on Matty for this one.
"These guys aren't robots. They're going to be out of synch once in a while. Matt usually makes adjustments, but he just wasn't able to do that tonight."
The homers helped stake Kendall Graveman to a 5-3 lead in his third major league start, but the right-hander also lasted just three-plus innings. Manager Bob Melvin pulled him after he walked Erick Aybar and C.J. Cron to open the fourth and ran his pitch count up to 73.
"I've got to go deeper in ballgames. There's no excuses," Graveman said. "I'm getting too deep into counts, and I'm not the kind of guy who can do that. But Dan did a great job coming in behind me."
Otero (1-1) bailed out Graveman by retiring the next three batters and the four-year veteran reliever allowed one hit over a career-high four innings (42 pitches) for the victory.
Ike Davis drove in the Athletics' first run with a bases-loaded sacrifice fly. The Angels responded in the bottom of the first with a two-out, two-run single by David Freese, who continued to second on the throw to the plate from center fielder Fuld and was thrown out by Vogt.
Athletics: RHP Jesse Hahn will be skipped one turn in the rotation to allow the blister on his middle finger to heal properly. RHP Jesse Chavez, who relieved Hahn after 65 pitches in Saturday's win at Kansas City, is penciled in to make the start instead on Thursday in the finale of this four-game series. ... 2B/OF Ben Zobrist, whose 18-game hitting streak against the Angels is the longest by any active player, sat out with an injured left knee that occurred on Sunday.
Athletics: LHP Drew Pomeranz (1-1) gave up four runs over five innings last Tuesday in a 6-1 loss at Houston, after pitching seven innings of two-hit ball in a 12-0 win over against Seattle in his season debut.
Angels: LHP Hector Santiago (1-1) allowed two earned runs over 23 1-3 innings in his four starts against Oakland last season. He faces an offense that has gone homerless in 322 at-bats against left-handers, dating back to last Sept. 7.