A bright start to the A's longest road trip of the season turned sour in Cleveland and didn't improve much from there.
Oakland took two of three at Yankee Stadium, but dropped all but one of the next seven games, including a 6-1 loss in the finale at Safeco Field on Sunday. The A's, who were 12-4, come back to the Coliseum back under .500 and six games behind Texas in the AL West.
"It didn't work out how we would have liked after New York," A's manager Bob Melvin said flatly.
The Mariners are a half game behind the A's after becoming the first team in the division to win a series against Oakland this year.
Last year at this time, the A's were 20-19, but they were eight games under .500 by June 1 and had to go 72-38 the rest of the way to make the playoffs.
"We've been there, so it's not something we're really worried about right now," A's starter Tommy Milone said. "We know what we have to do."
"We've got to get through it and not let it define our season," A's outfielder Brandon Moss said. "There are two ways to go: You can get through it or it can suck you dry and you look up and you're 10 games below .500. We've got to keep playing hard and keep believing, because we're much better than we've been playing."
Not much went right for Oakland, particularly in Cleveland where a game-tying homer by Adam Rosales in the ninth inning Wednesday was denied even after a conclusive replay. The A's got few breaks in the 10 games, but they also did not pitch well, with an ERA of 4.55; they did not hit much, batting .205; and their defense was inconsistent.