Other than a 3 1/3 inning outing when he got knocked out by a line drive in his finale last season at Texas, the outing was his shortest and the runs were the most he's allowed since giving up eight runs (seven earned) to the Angels in 3 1/3 innings on May 7, 2010.
"He's human, and I think sometimes we forget that," said Mariners manager Eric Wedge. "But he just had an off day."
The loss was Seattle's 11th in their past 12 road games and this one hurt more than usual, given it was their best pitcher getting pummeled.
Hernandez struggled from the get-go and not only got hit hard, but gave up three walks, hit a batter and had a wild pitch. The two-time All-Star threw 103 pitches before Wedge went to his bullpen after Hernandez had allowed five hits, including three doubles, in the fourth.
"Everything was flat today, my location was not that good, and they got me pretty good," Hernandez said. "The sinker was not there today. I felt good in the bullpen, but once I was in the game I was like, 'Where did my sinker go?' Sometimes it was up, sometimes it stayed right in the middle of the plate. And they took advantage."
The Indians were glad to jump on a pitcher who came in with a 5-3 record and 2.49 ERA against them in 11 previous starts.
"We were able, for the most the part, to lay off his offspeed stuff that starts in the zone and breaks down," said Indians designated hitter Travis Hafner. "I think we were able to get good pitches. Overall, everybody did a good job of putting good swings on balls, not trying to do too much."
While the Mariners had some moments -- including a 3-for-4 night with a home run by leadoff hitter Dustin Ackley -- they fell to 1-5 on the current road trip and 16-23 overall.
Ackley extended his hitting streak to 12 games, raising his average to .262, as he's been on an upswing since moving into the leadoff role. But he says that part is just a coincidence.
"As the season has progressed I've felt more and more comfortable. I don't think the leadoff spot necessarily has anything to do with that," said Ackley. "I think that's just more feeling comfortable at the plate, getting a little more confident, getting some hits here and there. I think all that's kind of helped me."
After 10 straight games without an error, the Mariners committed two on the same play -- allowing two runs to score -- during a four-run first for the Indians.
With Hernandez already struggling on his own, rookie catcher Jesus Montero committed a passed ball with the bases loaded to allow one run to score, then threw the ball into left field trying to pick Asdrubal Cabrera off third after pump-faking to second on a stealing Carlos Santana.
That allowed Cabrera to score from third, while Santana wound up racing home as well and crossed the plate when left fielder Chone Figgins' throw went wide for a second error. But Hernandez wasn't pointing at that as the problem.
"Errors are part of the game of baseball," he said. "You cannot be perfect all the time. You just have to forget about that and make good pitches. It was not the errors. It was me. It was my pitches."
But it was that kind of night for the Mariners. The Indians had a season-high five doubles by the fifth inning, by which time Hisashi Iwakuma was making just his fourth appearance of the season as a long reliever.
Iwakuma threw four innings of one-run ball to stem the tide, but by then the Indians were well on their way toward improving their American League Central-leading record to 21-16.
Ackley and Michael Saunders, batting in the No. 2 spot for the first time, combined to reach base six times with five hits and a walk. But the rest of the lineup didn't have a hit until Kyle Seager's single in the ninth.
The Mariners were 0-for-6 with runners in scoring position and are now 6-for-78 (.077)with RISP in that situation over their past 12 road games, including 3-for-33 (.091) on the current trip.