"It's very, very frustrating," said Gallagher, who gave up 10 earned runs on 11 hits and three walks over five innings. "I'm very disappointed in myself."
So thorough was the thrashing that A's manager Bob Geren seemed numb to the fact that the Twins appeared to pile on after building an eight-run lead through five frames.
Leading off the bottom of the sixth against righty reliever Santiago Casilla, Minnesota's Nick Punto stretched a single to center into a double and upended A's second baseman Mark Ellis with his slide.
"I thought it was just an aggressive play," Geren said.
Later in the inning, with the Twins up, 11-2, and baseball etiquette calling for a station-to-station approach on the bases, Joe Mauer was waved in from second base on Brian Buscher's bases-loaded single to right.
"Actually, I thought they did play station-to-station for the most part," Geren said.
Ellis absolved the Twins, too -- Punto in particular.
"I never have a problem with that," Ellis said. "You never stop playing the game. As soon as you stop playing the game, it'll come back and bite you. They were just playing hard. They play the game right here, always have."
One of four players acquired in the July 8 trade that sent Rich Harden and Chad Gaudin to the Cubs, Gallagher gave up three runs in the second inning, three more in the third and four in the fifth to extend his string of winless starts to seven. His last victory came in his Oakland debut on July 11, and he's been particularly ineffective in August, going 0-2 with a 12.75 ERA -- 17 runs in 12 innings over three starts.
Gallagher's velocity, which was in the mid-90s when he first joined the A's, hovered in the mid- to high-80s for most of Monday.
"He's not injured, but he definitely has some dead arm," Geren said. "I think he might just be fatigued."
Geren also suggested that Gallagher's next start might be skipped, and Gallagher seemed fine with that notion.
"The ball felt like a feather," he said. "It felt like I didn't have anything behind it."
For an inning and a half, at least, Gallagher and the A's were in control. Gallagher wiggled out of a minor jam in the bottom of the first inning, and a night after Ellis homered on the first pitch of the game, Kurt Suzuki homered on the first pitch of the second inning, lining an offering from Minnesota starter Slowey into the left-field seats to give the A's a 1-0 lead.
The Twins came roaring back in their half of the frame, though, getting a two-run homer from Buscher and an RBI triple from Denard Span. Minnesota All-Stars Mauer and Justin Morneau opened the bottom of the third with a single and an RBI double, respectively, and Morneau eventually scored on a single by Randy Ruiz, who scored on a two-out double by Brendan Harris to make it 6-1.
A's third baseman Jack Hannahan, a Minnesota native, gave his legions of fans something to cheer about with an RBI double in the fourth, but it was the Twins' fans cheering in the fifth as Gallagher gave up four more runs, including a two-run homer by No. 9 hitter Carlos Gomez.
Gallagher was still in the game at that point only because Oakland's bullpen was thin for the night.
"I knew we were shorthanded," he said. "I was just happy to make it through five."
Gallagher missed a scheduled turn in the rotation on Aug. 9 with shoulder soreness, but he insisted that his recent struggles are unrelated.
"I'm going to go sit down with the trainers and try to figure this out," he said.
Meanwhile, the A's will have to figure out how to beat lefty Francisco Liriano on Wednesday to win their first series since July 7-10 against the Mariners, who'll host the A's in the opener of a four-game set on Thursday.
"It's been a long time since we've won a series," Ellis said with a sigh. "It'd be nice to win tomorrow and have a nice plane ride to Seattle."