The American League West is theirs, but the A's still have more to play for as they head into their last series of the regular season, starting Friday against the Mariners in Seattle.
With their series loss against the Angels -- the only team in the last month to beat the A's in a series, which they have done twice -- the A's head to Seattle two games behind the Red Sox, who defeated Colorado on Wednesday evening, for the best record in the AL, which would secure them the top seed in the playoffs.
Boston plays its final three games in Baltimore, which figures to give the Red Sox more trouble than the Mariners against the A's, though the Mariners have played well against Oakland all season.
The A's have lost more games to the Mariners than any other opponent, compiling a 6-10 record against them heading into the weekend. So even while overtaking the Red Sox for home-field advantage throughout the AL playoffs is a long shot, maintaining their lead on the Tigers for home field in the AL Division Series is still in question.
"I think, record-wise, they've played us as tough as anybody," A's manager Bob Melvin said. "It's been a team that's matched well against us, and we're going to have to play good to beat them. They've been a challenge for us."
The A's will face Mariners ace Felix Hernandez in the series opener. His last start of the season will be his third in 2013 against Oakland. He has not allowed an earned run in 14 2/3 innings against the A's this season and has accumulated a 15-6 record and 2.60 ERA against them in 28 career starts.
Hernandez's most recent outing, against the Angels, was his first in 20 days because of a strained left oblique, and he walked four and threw 92 pitches in only four innings before manager Eric Wedge pulled him. There was also a swarm of bees that led to a 23-minute delay while he was on the mound in the third.
"We're going to keep a close eye, like we did last time," Wedge said. "We could have sent him out one more inning, but that wouldn't have been the smart thing to do as far as I'm concerned."
Hernandez said he had no issues with the oblique in that last start and felt 100 percent healthy. He is only 1 2/3 innings from his sixth straight 200-inning season, having already reached 200 strikeouts for the fifth consecutive year.
"It's important to me," Hernandez said. "That's why they have me here, to pitch, right? I've got to pitch. Every year, I try to reach 200 [innings] or more."
Bartolo Colon, meanwhile, has not allowed a run in his last 19 innings, which is an A's season high. The veteran right-hander is tied for the AL lead in ERA (2.64), tied for second in wins (17) and tied for third in winning percentage (.739).
A's could get Freiman back for final series
First baseman Nate Freiman has made steady progress in his rehab from an abdominal strain in recent days, giving the A's confidence he could be available off the bench for this weekend's set.
"He did well yesterday and didn't really feel it at all," Melvin said. "So he'll take batting practice in the cage today."
He has not played since Sept. 16, going just 2-for-12 in his previous six games, grounding into four double plays in that time. But he is still batting .306 on the season vs. lefties, with 48 of his 50 starts coming against southpaws.
Mariners no stranger to playing tight contests
In the 10th inning of Monday night's loss to the Royals, Kyle Seager tagged at third on a fly ball to left field and dashed home with the potential winning run, only to be tagged out at the plate by mere inches. The Mariners lost, 6-5, in 12 innings -- just another close loss in a season full of them.
"You're going to have some games where you get way out ahead, and some games where the other team does; it's the middle, close games that make your season," Seager said.
Seattle is 19-29 in one-run games and has lost four of its last five. Since 2011, the Mariners have had nearly one-third of their games decided by one run and more than a half have been decided by two or fewer runs.
Additionally, the Mariners have played a club-record 21 extra-inning games this season.
• A's slugger Yoenis Cespedes remained at designated hitter for a ninth straight time Wednesday, though he was on track to return to left field Friday, barring any setback with his right shoulder (tendinitis).
• A's outfielder Brandon Moss is batting .322 with 21 runs, nine doubles, 10 home runs and 27 RBIs over his last 31 games since Aug. 19. The home runs are second most in the AL behind 12 by teammate Coco Crisp, and the RBIs are third during that stretch.
• Mariners first baseman Justin Smoak, who hit his 19th home run of the year in Tuesday's 4-0 win over the Royals, has had a season of peaks and valleys. He has raised his batting average from .237 at the end of April to .274 in August before sliding back to .238 during a dismal September.
Jeff Kirshman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.