They were viewed as the A's potential long-term answers at first and third base. But those expectations have since cooled, and now they find themselves taking the field for Triple-A Sacramento instead of donning the gold and green for Oakland.
Barton, a year removed from leading the American League in walks (110) and ranking fifth in on-base percentage (.393), struggled to find a groove offensively. He hit just .212 without a single home run before being optioned to the River Cats on June 22.
"I've never failed this much in my life," Barton said, slouching against a wall inside the River Cats' clubhouse after a recent game. "Let's be honest, it's not something that anyone should go through, but it's life, there are bumps in the road everywhere and this is just one of them."
Kouzmanoff, on the other hand, was coming off a 2010 campaign that didn't live up to his own personal standards. The third baseman hit .247 in his first season with the A's and drove in a team-high 71 runs, but started this year with a .221 average and committed nine errors in 46 games before the A's optioned him to Sacramento on June 6 and outrighted him four days later.
"Defensively I wasn't getting my job done like I should have been doing," Kouzmanoff said. "Offensively ... I felt like I was starting to come around when the move was made. But what can you do?"
With the A's struggling to climb out of last place in the AL West and Barton and Kouzmanoff struggling to find their rhythms at the plate, the two find themselves at a career crossroads in the Minors.
After his successful 2010 campaign, Barton -- whom the A's franchise held in high regard after acquiring him in the '04 Mark Mulder trade -- never imagined he would be taking cuts in the Minors again. But as the games went by and his slump worsened, he could sense the move was coming to give him a chance to find his swing.
"When you start listening to what people are saying on the outside and start reading what people are saying, you kind of get a clue," he said. "I'll be the first one to admit that I didn't do my job when I was there."
Through three-plus weeks in Triple-A, Barton is still searching for his swing, and is still looking for the cause of his struggles. His shoulders, he said, have been banged up all season, but he isn't using it as an excuse for his performance.
The first baseman admitted he feels he has no power -- evidenced by his home run drought -- or bat speed. He has worked on the positioning of his hands, and he has taken advice from a plethora of sources, including Sacramento hitting coach Todd Steverson.
Steverson is no stranger to Barton. He spent the past two seasons as Oakland's first-base coach before moving to the River Cats, and has been coaching in the A's farm system since 2004. He believes most of Barton's struggles stem from the psychological aspect of hitting.
"Hitting is very mental, it's very intricate, and really it can be something that happens unconsciously to you," Steverson said. "Your habits that you got into unconsciously become habits, and you forget how to get back to where you were. It's tough to break them."
Barton, heading toward being eligible for salary arbitration for the first time, has yet to find a way to break those habits. He knows he will have to make adjustments -- finding consistency at the plate, making good contact and being confident -- if he wants a chance to be Oakland's answer at first base. In the meantime, Conor Jackson is playing there.
"The biggest thing for me is having my confidence because this game is tough, man, it can wear you down," Barton said. "If you're not mentally tough, then you might not be around long, and that's something I'm fighting right now."
The 25-year-old hopes he will be around a while, and he isn't ready to give up on an A's organization that hasn't given up on him. But with his confidence at a nadir, the player who was once expected to be a large piece of the puzzle has found himself contemplating what will happen if he can't regain his offensive prowess.
"It's a game of adjustments and maybe I haven't made my adjustments, I don't know," Barton said. "It's life. I'm 25 -- I have a long career if I decide to keep playing.
"I'm going to wait this season out, finish this season, and if I don't feel like anything's changing or anything's getting better, I might second-guess myself and think otherwise, see if there's something else out there for me. ... It just feels like I'm in Little League again, trying to learn."
While Barton foresaw his move to the Minors, Oakland's decision to send Kouzmanoff down and remove him from the 40-man roster took the third baseman by surprise.
He had not been in the Minors since making his Major League debut with the Indians in 2006, and it was a possibility he never once gave thought to, especially after the A's signed him to a one-year, $4.75 million contract to avoid arbitration in the offseason.
"I didn't see it coming," he said. "I was just uncertain. At that point I didn't really know what to do."
After the initial phase of uncertainty, Kouzmanoff has not pondered life without baseball like Barton has. But unlike his teammate across the diamond, he doesn't sound nearly as optimistic about his future with the A's, who have taken a liking to Scott Sizemore at the hot corner.
"You never know who's out there -- if a team needs to get a position player," Kouzmanoff said. "So far I'm happy with the way I'm playing right now, and I made the adjustment pretty well and I'm feeling a lot better. Now I'm just working on getting back up there."
Kouzmanoff has done just that, putting his head down and taking what Sacramento manager Darren Bush called a "professional approach" to his demotion. In 27 games with the River Cats, Kouzmanoff is batting .300 and slugging .575. His defense has improved, too, as he has committed just two errors in 28 games and has a .970 fielding percentage, compared to his .922 fielding percentage with the A's this season.
Steverson, who has worked with Kouzmanoff since the A's acquired him from the Padres prior to last season, has been impressed with what he's seen from the third baseman in all aspects of his game, and believes both infielders will persevere through this trying experience.
"They've been positive," Steverson said. "They could've come down here, looked at me and just told me to flip balls and let them figure it out themselves, but they've been really receptive to instruction, really receptive to change -- not major changes, but just change. I think once you realize you need to make a change ... it could be something totally different and it still works.
"I know Kouzmanoff has had some success and Barton's going to have success, and I'm sure of that because he's too good of a hitter not to. It's a matter of staying on a routine and getting your mind right. If you can't get your mind right it's a tough game."
Tom Green is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.