The 27-year-old Pauley, who vied for a spot at the back end of the Orioles' rotation last spring before going 9-12 with a 4.37 ERA at Triple-A Norfolk, became the latest unheralded arm to handcuff the O's, handing Baltimore a 6-5 series loss en route to his second career Major League victory.
"It's frustrating," said Orioles manager Buck Showalter, who watched his team get shut out Tuesday night by young Mariners lefty Luke French -- who, like Pauley, started the season in the Minor Leagues and had never started against the O's.
"You can watch all the tape you want to watch, but ... you don't go into it thinking this is a guy you should do this or that to. You see [outings like] that a lot [from] guys who are unheralded, so to speak, so far. But I don't take anything away from his performance."
Pauley, who has spent part of 10 different seasons in the Minors, allowed a pair of runs in the first before going on a run that included sitting down 13 consecutive hitters. Brian Roberts doubled to open the sixth, but Pauley got out of that jam and gave up just three hits through the first six innings, exiting after Matt Wieters belted a two-run homer in the seventh.
Pauley's performance, as shocking as it may have been to the crowd of 11,213 at Camden Yards, handed Baltimore its fifth loss in seven games and gave the Orioles little choice but to do the proverbial tip of the cap.
"He's got late movement, and it's tough to pick up at the last second," said right fielder Nick Markakis, who singled and scored off Pauley in the first inning but went hitless in his final four at-bats, including a game-ending line drive that deflected off closer David Aardsma to strand Cesar Izturis at second.
Wieters, who caught Pauley briefly last season while at Triple-A, said the key was his use of offspeed pitches, particularly a changeup that kept the Orioles' batters off-balance for most of the night.
So when the O's catcher saw a 3-1 pitch he could drive, he didn't hesitate. Wieters drove Pauley -- who angrily punched his fist into his glove -- from the game and reduced Baltimore's deficit to a solitary run.
"I don't think I could put that in G-rated form," Pauley said of his emotion following Wieters' blast over the right-field fence. "I was frustrated because it was a pitch I probably didn't need to make with the way the game was. I challenged him and lost."
But in the end, it was the Orioles who were tagged with an "L", falling to 10-6 under Showalter and dropping consecutive sets for the first time under their new skipper.
"The most disappointing thing was not winning the game," said O's starter Jeremy Guthrie, who battled through eight innings but was tagged with six runs (five earned) -- three of which came off rookie Matt Tuiasosopo's homer.
"He hit the exact same pitch yesterday," Guthrie said of the 2-1 slider he second-guessed moments before Tuiasosopo sent it 372 feet.
"It wasn't the right pitch, nor did I execute it like it should have been executed. He did a good job and hit it out of the ballpark."
Guthrie, who entered the game with the best second-half ERA in the Majors (1.51), wasn't nearly as dominant as he has been as of late. Still, after allowing a leadoff second-inning double to Jose Lopez and Franklin Gutierrez's infield single, Guthrie recorded the next two outs and looked poised to get out of the jam unscathed.
Tuiasosopo -- fresh off Tuesday's four-RBI night -- had other plans, sending Guthrie's pitch over the left-field fence for his second homer in as many games.
"I didn't feel that pitch in that moment," Guthrie said. "I had already shaken [the slider] two or three times in the inning. Sometimes you get lucky, you throw a pitch you don't feel and the guy pops it up, or you throw it in a good quality spot. But that was one of those times I didn't feel it and didn't execute it. If I could have thrown it low and away, there would have been a different result."
The same could be said for Tuiasosopo's eighth-inning catch, an on-the-run, diving grab that robbed Wieters of a potential extra-base hit that would have scored Adam Jones from second and tied the game.
"That catch, at the time, was as big as the home run," said interim Mariners manager Daren Brown. "I knew he was going to get close. He's an outstanding athlete and made a nice play on it."
The inning got started when Luke Scott -- who singled in both runs in the first -- laced a one-out double into left field, advanced to third on a balk and scored on reliever Jamey Wright's wild pitch. Wright was replaced by right-hander Sean White, who got Felix Pie on a comebacker to the mound but put the tying run in scoring position. Again, Tuiasosopo stole the show to keep the Mariners' lead intact.
"You can always, [in a] close game like that, go back and find the defensive play that made the difference one way or the other," Showalter said. "We made a couple of those, too. But because of the situation in the game and the inning, it certainly magnifies it a little."
And because of how good Guthrie had been, Wednesday's line looked worse than it was. Guthrie allowed five runs over the first five innings after giving up just four earned runs over his previous four starts -- a stretch of 28 innings. Still, he lasted eight innings on the hill, saving the Orioles' bullpen and giving the offense a chance to come back.
"It came down to a couple of pitches," Guthrie said. "Our team really battled, and it's unfortunate on a night like this I couldn't pitch better."
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Twitter @britt_ghiroli. This story was not subject to the approval of Major League Baseball or its clubs.