"They ran the [opening] kickoff return back and the game was over," manager Lloyd McClendon said after Oakland jumped on Young for five runs in the first.
While the Mariners gave Young eight days of rest after he went just 3 2/3 innings in his previous start in Boston, that didn't refresh the 35-year-old, who gave up two walks and four hits, including a two-run homer on Adam Dunn's first at-bat with the A's, before getting the early hook.
Young insisted he's fine physically, despite having his start pushed back from Saturday to Monday and then seeing things go south in a hurry.
"I feel good," he said. "I wouldn't take the ball if I didn't. Every pitcher goes through a period during the season where they don't throw the ball as well, and mine is right now. I'm going to get through it, I'm going to keep working and I'm going to finish strong."
McClendon said he'd talk to Young on Tuesday to see how he's feeling, but he wasn't second-guessing the recent decision to give all his starters extra rest last week prior to the September stretch run.
And he pointed to a 2 2/3-inning outing by Indians ace Corey Kluber in a 12-1 loss to the Tigers on Monday as evidence that lots of pitchers hit a rough patch this time of the year.
"We did what we did for a reason," said McClendon. "If you look at our starters the last two to three outings, they haven't been great. And if you look around the league at top starters throughout baseball, they haven't been great. The guy pitched in Cleveland today, it wasn't great.
"We did what we did for a reason, and that's to protect our starters. Will it be better next time out? Yes. They're trying to get over that hump, and they will get over the hump."
Top prospect Taijuan Walker pitched six innings of one-run relief for Seattle after being recalled when rosters were expanded Monday morning, but the A's staked Jason Hammel to an early lead, and he held Seattle to three hits in eight innings in his longest start of the year.
On the flip side, Young's shortest start of the 186 he's made since 2004 came at a bad time for the Mariners, who fell to 73-63 with their fifth loss in the past seven games and dropped 1 1/2 games back of Detroit in the chase for the American League's second Wild Card berth.
Young is now 12-7 with a 3.46 ERA in 27 games after running into an A's team that had been ripped by manager Bob Melvin on Sunday after getting swept four straight games by the Angels.
"I wasn't sharp, my stuff wasn't good," Young said. "I was flat. When I made pitches, they battled, fouled them off until they got a pitch to hit and then they jumped on it. They came out super aggressive. You could see, just the way they got in the batter's box, they were motivated and ready to go. And I didn't have it."
The A's scored one more run in the first inning than they had the entire four-game series in Anaheim and they did it against a pitcher who had put up a 2.25 ERA in four prior appearances against them this season.
"Chris Young's been a guy, you look at his numbers, he's been really good," Melvin said. "You look at his hits-to-innings pitched, the record, the ERA. He's no day at the beach and we've struggled with him as well a couple times. We needed a good game today."
After Lucas Luetge got the final out in the first after allowing Young's final run, Walker pitched the next six frames and allowed six hits and one run while retiring 10 in a row at one point.
Walker had two walks and five strikeouts in an 89-pitch performance that lowered his season ERA to 3.00 after three earlier starts with the club.
"I didn't want to see him today," McClendon said of his new long reliever, "but he did a nice job. He threw the ball pretty darn good."
"I felt really good," said the 22-year-old. "My fastball command was there, I was throwing in and out and the defense was making plays behind me. Me and [catcher Mike Zunino] were on the same page, just a quick pace and get the ball and go."
Oakland evened the season series with Seattle at 7-7 and is now 79-58 on the season, 5 1/2 games ahead of the Mariners with five games remaining between the two in the next 13 days.
Dunn, acquired Sunday from the White Sox, went 2-for-3 and was hit by a pitch. He lit up the sellout crowd of 36,067 with his 461st career home run as he became the 12th A's player ever to go deep in his first at-bat with the club.
"I didn't think it was a horrible pitch," Young said of the 1-1 changeup. "He's such a strong guy, he hit it well enough. He's a great hitter and a big addition to their lineup. It wasn't located as well as it needed to be, but it wasn't a horrible pitch either. Sometimes you tip your cap. I needed to limit it to that at that point and I didn't do it."
Shortstop Brad Miller drove a solo home run over the right-field fence leading off the sixth for Seattle's lone tally. It was Miller's ninth home run of the year, tied for the second-most of any AL shortstop.