OAKLAND -- What's been obvious for days, if not weeks, became official Tuesday night: The White Sox aren't winning the American League Central.

They suffered a 7-2 loss to the A's and were eliminated from contention. The White Sox fell 12 games behind the Minnesota Twins, who defeated Cleveland 6-4 earlier Tuesday night and clinched the Central crown when Chicago fell to the A's.

"It's disappointing for me, yes," White Sox manager Ozzie Guillen said. "You look back and you say, you worked all Spring Training through the summer and don't get what you want to get. I mean, it's another losing year, no matter what it is. I know we played hard, I know they tried hard, they did everything they could to finish where they wanted to finish. ... I'm not getting paid to have a good season. I get paid to win. ... We didn't do it this year."

The White Sox lost for the eighth straight game on Tuesday. It's the team's longest losing streak since losing eight straight in 2007, a skid that stretched from Aug. 11-19 that season.

The White Sox started this season 24-33, but they entered the All-Star break on a 25-5 run, matching the best 30-game run to end a first half in Major League history. They led the Central by a half-game over Detroit and 3 1/2 games over Minnesota at the break, fueling legitimate playoff hopes.

Then the second half began, and the Twins got unbelievably hot and started pulling away.

Even so, the White Sox trailed Minnesota by just 3 1/2 games on Sept. 6 when they were a season-high 17 games over .500 at 77-60. Since then, they've been frigid, going 2-12 as their playoff hopes vanished.

"Obviously that's why we play this game is to get in the playoffs," said a frustrated Mark Buehrle, who took the loss Tuesday night. "We put ourselves in such a deep hole at the very beginning. Then we went on a good run for a little bit.

"I think everybody kind of knew that wasn't going to continue that way the whole season long. We brought ourselves back into contention and gave ourselves a chance, but these last couple weeks we haven't played well enough to even deserve to be in there."

Buehrle fell to 4-13 lifetime against the A's and 1-7 at the Oakland Coliseum. His only win in Oakland came July 23 this season when he pitched a complete game, allowing four hits in a 5-1 White Sox victory. This time he gave up 11 hits and five runs, exiting after the sixth.

"This is kind of getting old," Guillen said of the eight-game losing streak. "Oakland has a good pitching staff. The last couple guys we faced are pretty good. We attacked them pretty good today.

"I don't care if you have 10 games left or 20 games left, losing is not fun. To me it's not fun, and I know for those guys either. I'm not saying we're not trying, but it starts getting old. Hopefully we start to settle down and have some more fun in the field. ... It's not fun losing every night."

The A's took a 1-0 lead in the first when Kurt Suzuki drove Daric Barton home with a groundout. They made it 2-0 in the third when Suzuki ripped a double off Buehrle, scoring Barton from first. Oakland added three more runs in the fifth. Cliff Pennington hit a two-run double then scored Barton's bloop single, making it 5-0.

The White Sox got to A's starter Trevor Cahill for single runs in the fifth and sixth. In the fifth, shortstop Alexei Ramirez led off with a double and eventually scored on Brent Morel's groundout to short.

Juan Pierre led off the sixth with a single, stole second, went to third on Omar Vizquel's single and scored when Manny Ramirez hit into a double play.

Pierre stole his AL-leading 59th base in the sixth inning to move into a second-place tie with Scott Podsednik on the team single-season list. It was Pierre's 518th career steal, tying him with Patsy Donovan's on baseball's all-time list.

Guillen tried to shake up his lineup and pack it with left-handed hitters to face Cahill, a right-hander with a nasty sinker.

First baseman Paul Konerko, right fielder Carlos Quentin and center fielder Alex Rios were all out of the lineup. Mark Kotsay started at first, Mark Teahen in right and Alejandro De Aza in center. De Aza made his first start since being called up from Triple-A Charlotte on Sept. 1.

Nothing seemed to work, which has been the story of the White Sox nosedive.

"We had a lot of injuries the last month of the season," Vizquel said. "Our bullpen is not the same, and I think that really hurt us at the end of the season.

"The offense hasn't been producing, either. We struggled a little bit the last month of the season. So the combination of both is not very good."