SEATTLE (AP) -- - Wie-Yen Chen threw one of his finest games in the major leagues, allowing just five hits over eight innings in Baltimore's 4-0 victory over the Seattle Mariners on Thursday night.
What everyone wanted to talk about, however, was his defense.
Chen (11-3), who has won his past four starts, set the tone in the first inning when he bounded off the mound, gathered a slow roller and glove-flipped the ball to the plate to prevent a run.
''That was a little bit of a momentum change there,'' Orioles manager Buck Showalter said. ''Then he showed how to get people out after that.''
Delmon Young hit a three-run homer in the Orioles' four-run third inning and that was all Chen needed as he scattered five singles, walked one and struck out three, matching his career high for innings pitched.
His 11 wins ties him for third-most in American League. On the road, Chen is 6-1 with a 3.94 ERA in nine starts.
Darren O'Day finished with a routine ninth inning.
It was Baltimore's eighth shutout. The Mariners have been shut out 12 times, tying Tampa Bay for the most in the American League.
Chen's only hint of trouble came in the first. James Jones walked and stole second, the rookie's 20th of the season.
After a groundout, Robinson Cano dribbled a ball in front of the plate. Chen scooped and flipped it with his glove to catcher Caleb Joseph, who tagged Jones as he slid in head first.
''They actually practice that play in spring but it's one of those things people think you're killing time with pitchers,'' Showalter said. ''But it came into play today.''
Mariners manager Lloyd McClendon protested the call but it was crew chief Fieldin Culbreth who initiated a TV replay review to determine if Joseph illegally blocked the plate.
After a review of 3:45, the original call was confirmed.
''I was going on contact and his foot was there in the way,'' Jones said. ''I didn't understand the rules, if I could run through him or I didn't know what to do but he was definitely in front of that plate.''
Joseph said he's ''pretty clear on the rules.''
''You try catch it and make the tag,'' he said. ''The last thing in my mind is where you are position-wise. But that's an important aspect because of the new rules. We got it right tonight. We got it wrong about a month or so ago so it feels good to get it right this time.''
McClendon still isn't so sure.
''I can't go out and argue after the decision's been made,'' he said. ''I'm just a little puzzled. He didn't have the ball, his foot was in front of the plate, he caught the ball and he dropped (his knee). To me, that's blocking the plate.''
Hisashi Iwakuma (8-5), who had won his previous three decisions, lost for the first time since June 25. He went seven innings, allowing four runs and seven hits. He struck out five without a walk.
Iwakuma, who had just two three-ball counts, has not walked a batter in a club-record five straight starts, a span of 35 2-3 innings. He is second in club history in walk-less innings behind Cliff Lee's 38, set in June 2010.
Iwakuma has 33 strikeouts against no walks in those five starts.
The Orioles began their four-run third with singles by Ryan Flaherty, Joseph and Nick Markakis.
Markakis' single drove in one run and on the next pitch Young hit his fourth homer. It was the Orioles' 123rd of the season, tying Toronto for the most in the majors.
Young said he wasn't thinking home run ''just something to get us the runner in from third.''
Dustin Ackley of the Mariners had a single in the second to give him a seven-game hitting streak and push his July average to .373.
NOTES: Beyond the Mariners' acquisition of DH Kendrys Morales from the Twins before the game, the club also added two players from Triple-A Tacoma to the roster. Jesus Montero was called up for a second stint and started at DH. Chris Taylor started at short in his first major league game and singled in the fifth. When he called his parents in Virginia Beach to tell them the news, Taylor said, ''it was tough to hold it together. That moment is something you're never going to forget. Talking to them on the phone, telling them the news, hearing their voices, how excited they were, it's just an indescribable feeling.'' To make room, the club sent RHP Taijuan Walker back to Tacoma and placed INF Willie Bloomquist (right knee contusion) on the 15-day DL. . The Orioles acquired INF Jimmy Paredes from Kansas City for cash considerations. He will report to the minors.