We know everything about baseball these days. We can tell you that Mike Trout leads the majors in batting average on low pitches. We can tell you which starting pitcher throws his fastball with the most velocity on average (Stephen Strasburg) or most often (Bartolo Colon) or the vertical break Justin Verlander gets on his curveball (a lot).

On the other hand ... we don't know anything.

How else do you explain the Oakland Athletics? Nobody expected the A's to be any good this season. Many expected them to lose 100 games. I heard one national radio analyst declare that the A's could lose 120 games. I'm not sure the A's believed in the A's, not after trading Gio Gonzalez and Trevor Cahill in the offseason in yet another rebuilding plan. Dan Szymborski's ZiPS model was a little more optimistic, projecting in March that Oakland would win 70 games.

But here are the A's at 51-44 after an exciting four-game sweep of the New York Yankees: Four one-run victories, two in walk-off fashion, including Sunday's 5-4, 12-inning thriller during which Seth Smith tied the game with a home run in the bottom of the ninth and Coco Crisp's two-out flare scored Derek Norris with the winning run. It may have been the most electrifying four games any team has played this season. Just like that, the A's are playoff contenders, tied with the Orioles for the second wild card and just a half-game behind wild-card leader Los Angeles.

Yes, maybe our knowledge tells us the A's are still last in the American League in runs scored and last with a .228 batting average. Maybe our knowledge tells us they're too young, too inexperienced, too lucky with those five straight one-run wins and a major league-leading 11 walk-off wins.

But why not the A's? They've allowed the fewest runs in the AL -- 38 runs fewer than any other club. Too young? Can't hit? I'm sure in late July of 1969 skeptics said the same thing about the New York Mets. I'm sure in July of 1991 many believed the Atlanta Braves, who had finished in last place the previous three seasons, were too inexperienced and just riding a wave. In 2008, we waited for the Tampa Bay Rays to fall apart.

Sometimes, as we apply our knowledge, we too easily ignore the emotion of the sport, strip it down to numbers, statistics and probability. Probability. That's not the same thing as certainty. A's general manager Billy Beane undoubtedly can see this weekend's results and think back to his 2002 club that won 20 games in a row. What was the probability of that, even from a team far superior to this one?

But as A's outfielder Smith said after Sunday's dramatic comeback and win, "I don't think there was anybody in the dugout or in the stands who didn't think we were going to win."

Believe.

Heck, even the numbers weren't complete disbelievers in the A's -- ZiPS gave Oakland a 1.8 percent chance of making the playoffs. That's larger than zero.

How did the A's get here? Five key reasons:

1. Josh Reddick

He's been one of the best players in the AL, ranking third among AL position players in Baseball-Reference WAR behind Trout and Robinson Cano, at 4.1 wins above replacement. Reddick is hitting .271/.349/.529 with 21 home runs and 19 doubles, great numbers considering Oakland is a tough place to hit.

2. Yoenis Cespedes

When Beane gambled and signed Cespedes to a four-year, $36 million contract, even the most optimistic of observers thought it would take him a year to adapt to major league pitching. Instead, he's providing a big presence in the middle of the Oakland order, and despite going 0-for-5 on Sunday is hitting .299/.358/.530. Led by Reddick and Cespedes, the A's ranked third in the AL in home runs in June and rank third in July. Yes, the offense was terrible in April (.211) and May (.210), but it's been respectable of late. (Buster Olney wrote more about Cespedes on Sunday.)

3. Young starters

The A's lead the AL with a 3.69 rotation ERA. Yes, their home park helps, and skeptics will point to a low strikeout rate (5.93 K's per nine innings) as a possible indicator this rotation will eventually implode. However, maybe that's misreading the stats a bit. Colon has walked 19 in 19 starts; rookie lefty Tommy Milone has walked 26 in 19 starts; Travis Blackley has walked 10 in his eight starts; ace Brandon McCarthy, out since June with a bad shoulder but scheduled to throw this week at the club's spring training facility, walked 19 in 12 starts. This isn't a staff that beats itself. That roll call doesn't include Oakland's most impressive starter, rookie Jarrod Parker, the key acquisition in the Cahill trade, who is 7-4 with a 3.00 ERA in 16 starts. He's the one Oakland starter whose stuff grades out as top-of-the-line and he's held opponents to a .223 average.

4. Ryan Cook and Grant Balfour

The rookie All-Star Cook allowed his first two home runs of the season during the four games against the Yankees, but he and Balfour give the A's two nasty right-handers at the back of the 'pen. Opponents are hitting .115 off Cook and .185 off Balfour. But this 'pen has depth: Former position player Sean Doolittle has a 29-4 SO-BB ratio since his recall, Jerry Blevins is a solid lefty who can be stretched out against righties (he pitched two innings to get the win on Sunday) and Jordan Norberto and Jim Miller provide decent quality.

5. Intangibles

Yes, let's put it out there. Emotion, energy, the thrill of the unexpected. It means something. Maybe we can't quantify it. Maybe there isn't a number we can point to that analyzes it. But the something is there with this club right now.

"It definitely feels good to battle and be victorious against the best teams, on paper, in the game," Crisp told MLB.com after the game. "You can look up and down a lot of lineups like Detroit, or the Angels, the teams with high payrolls. Obviously they have high payrolls for a reason, because the players on the team deserve it. When we battle against those guys and come out with wins, it's definitely a great feeling."

The A's are riding a big wave right now. Maybe the team with baseball's lowest payroll can ride it further than anyone imagined.

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