SEATTLE -- Oakland manager Bob Melvin had a concise assessment of starter Jarrod Parker.
"He's good," Melvin said.
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The A's mustered just two hits against four Seattle pitchers, but both left the park.
Coco Crisp hit his second homer of the season on the second pitch of the game. Yoenis Cespedes hit his ninth in the seventh inning of Hisashi Iwakuma (1-1), whom he faced in the 2009 World Baseball Classic, to break a 1-1 tie.
Parker (4-3) allowed three hits and walked four. He's given up just two earned runs over his last 20 innings, going 2-0 in those three games, and has a 2.57 ERA overall.
Oakland acquired Parker, closer Ryan Cook and Collin Cowgill from the Arizona Diamondbacks for Craig Breslow, Trevor Cahill and cash Dec. 9, 2011.
"We're very pleased with what he's doing," Melvin said. "Did we expect him to be able to pitch games like this? Absolutely."
"We traded a prominent All-Star who is under control and young for that. Shows you what we think of him," he said.
Parker's third consecutive powerful outing put him in elite company. He joined Dwight Gooden as the only pitchers to allow one run or fewer in nine of their first 13 starts since 1918.
Cook pitched around an error and a walk in the ninth to record his sixth save. He struck out Ichiro Suzuki with the tying run on second and the go-ahead run on first.
Seattle starter Kevin Millwood left the game after just 2 2/3 innings after again straining his right groin. After retiring Kurt Suzuki on a grounder, Mariners manager Eric Wedge and trainer Rick Griffin visited Millwood on the mound and decided to remove him. Hisashi Iwakuma replaced him.
The 37-year-old Millwood left the Mariners' combined no-hitter June 8 with the same injury after pitching six innings. Though the right-hander did not go on the disabled list, he didn't pitch again until June 16 against San Francisco.
"I don't think it is anything too serious," Wedge said.
John Jaso homered in the Seattle second, tying it at 1. Parker walked Dustin Ackley and Brendan Ryan, then advanced them with a wild pitch. But, he finished his 29-pitch inning by striking out Suzuki on a high 3-2 pitch.
Parker settled in afterward. Only Jaso gave him trouble, reaching base three consecutive times.
Cespedes has hit two home runs in two nights, flashing the power he showed earlier in the season prior to an injured left hand that put him on the disabled list.
Grant Balfour took over for Parker in the eighth and allowed a one-out double to Kyle Seager. Balfour retired Jesus Montero on a fly ball and Michael Saunders on a lineout.
The A's allowed seven hits Tuesday night, and allowed 63 hits over the prior 12 games, the fewest by an Athletics team over a 12-game span since 1916. ... Mariners reliever Charlie Furbush has recorded at least one strikeout in 17 consecutive appearances, which is tied for the sixth-longest streak in Seattle history. It's the longest such streak since a 21-game run by Rafael Soriano in 2003.