MESA, Ariz. -- The Oakland Athletics hit 146 home runs in 2014. In a huge roster overhaul that would stun even Charlie Finley, the players who hit 106 of those homers are playing for somebody else in 2015. Josh Reddick, the only holdover on the team who reached double digits in homers for Oakland last year, is already injured and due to miss 4-6 weeks with his latest injury.

So you have to ask: Where is the power going to come from in 2015? Replacing the A's previous power trio of Josh Donaldson, Brandon Moss and Yoenis Cespedes in the middle of the order wouldn't be easy under the best of circumstances. But the A's didn't pick the best of circumstances. Instead, A's general manager Billy Beane took not just one but three chances in picking up Ike Davis, Billy Butler and Brett Lawrie. It's a disparate trio of sluggers with demonstrated power but also demonstrated handicaps.

Butler was the big-money addition, as Beane spent $30 million on the hitter, who should primarily DH. He's also coming off the worst year of his career, failing to slug .400 (league average was .411 last year), while posting his worst on-base percentage (.323) and worst walk rate (6.8 percent).

"Everything [last year] was career-low," Butler said ruefully. "I wasn't being as selective as I should have been. I had a tough time making adjustments for the first time in my life. It took longer than it should have taken; I can't tell you why."

Starting slowly last season, he'd started to press, earning himself a steady diet of pitches low in the zone or parked on the outside corner. A slow righty slugger in the truest sense of the term, he was hitting more ground balls. (What Paul Konerko liked to call "death" for players like himself.) Butler managed a small in-season comeback, producing a .740 OPS in the second half, almost exactly the average for a DH last year (.744).

"Pitchers are definitely being careful," Butler said. "But if you get some protection on a team with the same philosophy, you can make them throw strikes. I think I went out of the zone too much last year, getting away from who I am."

Perhaps more troubling, Butler's power numbers were also down in 2013, dropping almost 100 points from his 29-homer career year in 2012. His slugging percentage dropped from .510 to .379 across the last three seasons.

But Butler definitely relishes the challenge of providing the A's plenty of bang for their bucks and getting with the program in Oakland to help them generate offense. "I'll definitely take a lot more pitches [this year]," Butler said. "It's just who I am."

Similarly, it wasn't so very long ago that it seemed Davis would have a huge career. He put up a .791 OPS as a rookie with the Mets in 2010, and hit 32 home runs for them in 2012. But after losing most of 2011 and a big chunk of 2013 to injury and ineffectiveness, he comes to Oakland with two big problems: He has no demonstrated track record for consistency at the plate, and he was still battling Valley fever in 2014.

"Ever since I hurt my ankle [in 2011], I've had to adjust," Davis said. "The swing that I had before, it didn't feel right. I couldn't replicate it at all. So every year, I've had so many different stances, so many different swings, and finally I think I've found the swing that's going to work consistently. For a while there, every week was a new thing. And doing that at the major league level isn't easy; you don't want to be the man of a thousand stances."

Last year's trade to the Pittsburgh Pirates helped Davis find some consistency: He kept his walk rate around 15 percent, cut his swinging strikes and strikeouts to career lows, and he stopped being a dead pull hitter. In the second half, his power began to come back, as he cranked out an isolated slugging clip north of .200 for the first time since the 2012 season.

Davis credits that time with the Pirates, saying, "The whole staff they had over in Pittsburgh was instrumental in helping me become a better hitter. I feel like I had good at-bats, but I'm still learning, still trying to become a better hitter, and not just a guy who's swinging for homers."

And then there's the debilitating fatigue that comes with Valley fever, a fungal disease that sapped the career of NBA guard Johnny Moore in the '80s and wiped out first baseman Conor Jackson more recently. Davis is giving it his best shot.

"I've talked to Conor about it, and it really ended his career," Davis said. "When I was going through it, that almost felt like that was a possibility. But I battled back; there's nothing you can really do. The only thing they can really do for it is, you take [antifungal medication] for eight months. It's supposedly the worst thing for your body, so I didn't take it.

"I want extra-base hits. Whether it's doubles or homers doesn't really matter. I'm definitely a tougher out than I used to be. A lot of people reinvent themselves in Oakland. I'm definitely looking forward to it."

Considering that in a three-year stretch, Davis broke through, broke down, and then bounced back, can you blame him if even he isn't quite sure what kind of hitter he might still develop into?

And then there's Lawrie. Like Donaldson, his predecessor, he's a tremendously gifted defender at the hot corner. Unlike Donaldson, Lawrie broke through immediately, busting out for a .953 OPS in 43 games for the Blue Jays in 2011. But following that tantalizing taste of greatness, he spent big chunks of each of the past three seasons on the disabled list while failing to come even close to his 2011 production, parking in the .710-.730 OPS range.

One big problem for Lawrie is his approach to hitting. He stands almost directly over the plate, routinely risking getting hit by the pitch -- and getting hit, and hurt when he gets hit in the face, fingers or hands. But unlike either Butler or Davis, reinvention doesn't seem to be his thing, at least where his setup and approach at the plate are concerned.

"I've been hit in the same spot my whole career; that's how it goes sometimes," Lawrie said in a high-speed declaration. "Break bones, stuff happens, that's baseball. I'm not going to get off the dish because I got hit by a pitch. I'm not going to cater to the pitchers; that's definitely something I'm not going to do."

Lawrie will be just 25 years old in 2015, but he still has to demonstrate an ability to stay healthy, having missed 50 games in 2011, 32 in 2012, 54 in 2013 and 91 in 2014. But like the others, he too has a silver lining: Before his latest injuries ended his season, his power numbers started to improve last year, as his isolated power (ISO) jumped to .174.

If nothing else, in making this change from last year's sure thing to this year's maybes, the A's very deliberately got younger. The 2014 A's had the third-oldest average batters' age in the American League. Donaldson and Cespedes will be in their age-29 seasons, Moss his age-31 campaign this year. They're all older than Butler (29), Davis (28) and Lawrie (25).

The A's know all about the recent poor performance from this trio, and they nevertheless bet on the upside with every one of them. That may sound crazy, but remember where they're coming from in terms of recent experience. Moss was found on the scrap heap with a career .236/.300/.382 line. As a member of the A's, he increased his isolated power from his old career mark of .146 to .249 wearing green and gold from 2012 to 2014. Until the A's moved Donaldson out from behind the plate in 2012, you could not have predicted his development into a spectacular defender and MVP-caliber hitter at third base. Reddick wasn't pegged for the 32 homers he hit in 2012.

So I get how all that should engender a certain amount of confidence. The A's have enjoyed a remarkable recent run of coming up with power when they weren't expected to, especially considering they're often rifling through the bargain bins. That's especially tough in today's day and age -- there are plenty of smart organizations parsing performance and sifting through stats to define player potential and player value. But if Butler, Davis and Lawrie don't bop, the A's won't have a bopper.

Christina Kahrl writes about MLB for ESPN.com. You can follow her on Twitter.