OAKLAND -- A's general manager Billy Beane enjoys pushing baseball's boundaries, but there are baseball truisms that he doesn't question.

One is that the best way to improve a team's starting rotation is to improve the bullpen.

Beane has done that and more since the end of Thanksgiving, adding closer Jim Johnson from the Baltimore Orioles and durable setup man Luke Gregerson from the San Diego Padres.

The A's also added center fielder Craig Gentry and reliever Josh Lindblom from the Texas Rangers and signed free agent left-handed starter Scott Kazmir, late of the Cleveland Indians.

Together with holdover setup men Ryan Cook and Sean Doolittle, and versatile Jerry Blevins and Dan Otero, Johnson and Gregerson give the A's as deep a bullpen as any in the game. And with Johnson due to get close to $11 million in salary arbitration, the A's could wind up spending close to 30 percent of their payroll on the bullpen.

After losing Grant Balfour to free agency, the A's thought about using Cook or Doolittle to close.

"Not being the closer is absolutely not a problem," Doolittle said. "I'd be lying to say I didn't want to go to spring training with a chance to win the closer role. But when the opportunity comes to get a guy like Jim Johnson, you can't pass that up. He'll make our team better.

"We (Cook and Doolittle) will be right back where we were. And we'll have a good solid bullpen. I don't see either one of us letting ego get in the way or moping. Our time will come."

Gregerson, 29, who closed upon occasion with San Diego, went 6-8 with four saves and a 2.71 ERA in 2013, holding hitters to a .203 batting average. He's pitched in the eighth and ninth innings, and he's looking to do the same with the A's.

"I feel I've done well coming in in pressure situations," he said. "I hope to do that in Oakland."

Beane is spending as if the A's time is now. He committed $22 million over the next two years to Kazmir, a one-time hard-throwing lefty who has discovered his fastball again.

Kazmir could wind up being the club's highest-paid player.

"I'm glad to see that they are opening up the pocket books a little bit," third baseman Josh Donaldson said, "and spending a little bit more money to take this team to the next level."

The A's have won the American League West each of the last two years but bowed out in the A.L. Division Series. Is this the team that will go further?

Gentry said it might.

"I'm excited about it," Gentry said. "I'm hoping I can help that team win maybe another title."

The A's had to let some players go, but no big names. They traded Seth Smith to get Gregerson, Jemile Weeks for Johnson and former first-round pick Michael Choice to get Gentry.

The plan is for a third consecutive AL West title and maybe better success in the playoffs.

"We have no five-year plan," Beane said. "We have a one-year plan. We are either all in or all out. If the time comes that we think we are not at that level, we'll be all out. We're not going to straddle the fence."

Josh Reddick, who will share outfield time with Gentry, is excited about the flurry of moves.

"I think we will really be good," Reddick said from his home in Georgia. "We've made some good trades and one good signing. A guy like Kazmir will mix up the other lineup, getting a hard-throwing lefty out there. Johnson is one of the elite closers. He didn't have quite the record he wanted last year, but he still saved 50 games.

"We did get rid of a great player in Choice, but we are getting a great guy back. Gentry can hit, get on base, run and play defense. He can track down a lot of baseballs. He's run down quite a few on me."

  • Choice came up with the A's for a look in September, hitting .278 in nine games after hitting .302 with 14 homers for Triple-A Sacramento. But the A's first-round pick in 2010 is from suburban Dallas. "It feels good to know that I'll be playing at home," Choice said. "It's a bittersweet feeling to be traded away from the team that drafted you. But I did get the chance to experience the big leagues with the team that drafted me, so that was a great experience.''

  • In Lindblom, the A's are getting a pitcher with some promise who has bounced around, playing for three teams the last three seasons. "Lindblom can start and throw long relief," manager Bob Melvin said. "To get players you want like Gentry and Lindblom, you have to give up some quality, and unfortunately for us it took Choice to get them."

  • Reddick, who had surgery on his right wrist after the season, said he starts physical therapy Wednesday. He's set Jan. 1 as a goal to start swinging a bat.

  • Bostick, the minor leaguer going to the Rangers, hit .282 with 14 homers and 89 RBIs at Class-A Beloit.

    Two days in December
    Billy Beane and the A's shifted their roster around over the last 48 hours. Here are the key players who will be coming and going:
    COMING
    Luke Gregerson, rp (trade)
    Craig Gentry, of (trade)
    Scott Kazmir, sp (free agent)
    Jim Johnson, rp (trade)
    GOING
    Michael Choice, of (trade)
    Jemile Weeks, inf (trade)
    Seth Smith, of (trade)

    LEAVING*
    Bartolo Colon, sp (free agent)
    Grant Balfour, rp (free agent)
    *The A's are not expected to resign Colon or Balfour.
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