SEATTLE -- From a comebacker off his leg, to a tight strike zone, to a challenged call on a play at the plate, James Shields could point to a myriad of factors that contributed to his worst start of the season.
Instead, the veteran right-hander brought up the long-standing mantra of not getting ahead of the hitters.
Shields tied his career high of 10 runs allowed, which came on eight hits and four walks over 2 2/3 innings in San Diego's 16-4 loss to the Mariners at Safeco Field on Tuesday.
"Just getting behind in the count, walking guys," Shields said. "All my damage was two outs. If I bear down and get those outs, it's a whole different ballgame. They might not score any runs, really to be honest with you. Just kind of one of those days. That's a good-hitting team over there. I didn't do my job today, and we've got to move forward."
With two out in the first, Shields walked Robinson Cano and Nelson Cruz, and Kyle Seager followed with an RBI single.
With two outs in the second, the Mariners loaded the bases on a walk and two singles, and Shields walked Cano to force in a run. Cruz followed with a two-run single. Seth Smith reached back with his hand to touch home ahead of a one-hop throw from left fielder Melvin Upton Jr. to score the second run.
The Padres challenged, but the on-field call was ruled to stand after a review of almost three minutes. Kyle Seager then followed with a three-run homer to make it 7-1.

Smith's two-out three-run homer in the third ended Shields' day with the Padres down 10-0.
"I feel like I threw a lot of quality pitches today. Whether they were strikes or not, that's not up to me," Shields said. "But I didn't do a very good job of getting ahead of hitters."
Shields has had other rough outings over his career but moves past them, he said.
"It happens to everybody," Shields said. "Obviously, you don't want it to happen to yourself. But, it happens. I'm not really one to dwell on my games, whether I do good or do bad. I just move on to the next game and try to help my team win a ballgame."
Shields also said the ball hit off his calf by Franklin Gutierrez to open the second inning did not affect his pitching, even though it brought the trainer out to the mound.
"It caught me pretty square, but I'm fine," he said. "It's just kind of one of those when you get hit it stings a little bit, but you get over it and move on."
Shields also had good view of the contested play at the plate.
"I was right there, myself. I was kind of late backing up and to me it didn't look like he touched the plate at all on the live view," he said. "Obviously, the instant replay you can't really tell, but to me on that instant replay it looked like he didn't even touch the plate even then. Regardless, I didn't get my job done today."