OAKLAND, Calif. — Much has been made of the A's having the best record in baseball from the middle of 2012 to the middle of 2013.

OAKLAND, Calif. — Much has been made of the A's having the best record in baseball from the middle of 2012 to the middle of 2013.

Dating to July 1, 2012, the A's are 105-61. The .633 winning percentage, best in the major leagues during that stretch, owes much to the 55-26 finish to last season

But, at 48-35, this year's edition of the A's isn't far off the pace, and success is coming in a more sustainable fashion.

Last year, the A's did it with pitching and by hitting home runs — the most in the majors after the All-Star break.

This year, the A's still are pitching well and hitting some home runs. But the big change is in their ability to get on base. And, unlike home run hitting, on-base percentage is at less risk of going into a slump.

After 81 games this season, the A's had 313 walks, most in the big leagues.

"Of all the stats in baseball, on-base percentage has the biggest correlation to winning," general manager Billy Beane said. "So, yes, I'd say this way is more sustainable. Ideally you'd like to have a high on-base team that is a high home run team, too, but those are generally the most expensive teams there are."

It was perhaps predictable that the A's home runs would fall off from the furious rate at which they hit them last year. But it was less predictable that the hitters would get on base more.

"It's a different approach at the plate," hitting coach Chili Davis said. "We can hit home runs, but we're not just the power team we were noted to be the second half of last year.

"We've come out to show this year that we're not just about power. We're a patient team, a selective team. We will wait for our pitch. And if you miss, we'll take a good swing at it."

As good as the A's were in the second half last season, their on-base percentage in the final 81 games was only .319. The first half this season has seen some occasional rough sledding for the A's, but their on-base percentage is at .327 and has been rising.

Josh Donaldson leads the A's with a .384 OBP, up from .289 last season. Newcomers Jed Lowrie (.381) and John Jaso (.377) are second and third.

The A's win Friday over the St. Louis Cardinals in Game 81 was probably the centerpiece of their patient approach. Cardinals rookie Shelby Miller had to throw 51 pitches in the second inning, and that still wasn't enough to dig him out of trouble. He was lifted after five runs had scored.

"That's the way you'd like to be every game," Davis said. "There are days when you'd wish we were more like that than we are. We get away from it sometimes with quick at-bats. But we have a lot of quality at-bats for the most part."

The A's, fifth in the league in scoring, can work over a pitching staff, to be sure. At the same time, A's pitchers don't often allow the other side to do the same. They issued only 201 walks over the first 81 games — a pace that would break the team record for fewest walks allowed (415).

"That's really the strength of our staff," pitching coach Curt Young said. "Word is out. We're known as a club that's going to throw strikes."

Doing that puts the onus on the other side to be ready to hack at pitches early in the count. Sometimes the hitter will win. But A's pitchers are good enough up and down the roster that much of the time they will win the one-on-one battles.

"We have pitchers who are going to create action and make things happen," Young said. "And we've shown that we're not going to beat ourselves. It was a strength last year, and we've seen it's a strength this year, too."

The A's have gotten big performances from Donaldson (.316, 13 homers), Lowrie (.309), pitcher Bartolo Colon (11-2, 2.79) and closer Grant Balfour (19 saves in 19 tries). Most of the rest of the pitchers have been above average, as has center fielder Coco Crisp (.274, nine homers, 46 runs).

It's nice to have had a first half like this," Beane said. "But the thing most people don't realize is that we've historically always been a better second half team."

Repeating history could make for some rocking times in the Coliseum the final three months of the season.