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03/05/12 8:32 PM EST

Barton shut down after latest cortisone shot

PHOENIX -- Daric Barton was scheduled to have his second cortisone shot in his surgically repaired right shoulder on Monday and will be shut down for another three days.

Barton won't be able to throw for at least a week, and his chances at an Opening Day roster spot are slimming by the day. Manager Bob Melvin is not ready to say as much, but at the same time is being realistic about the situation.

"Certainly he's going to have to be able to throw and play first base, and certainly that's going to be a little longer to come," Melvin said. "I don't want to rule anything out at this point, but you can count the days."

After experiencing some soreness in his shoulder while attempting to throw last week, Barton underwent an arthrogram MRI -- it delivers a series of images using a dye injection -- that also included a cortisone shot to help calm down the shoulder. The team's medical staff, in also consulting with Dr. Lewis Yocum, who performed Barton's surgery, then decided a cortisone shot in his biceps tendon would hopefully deliver the last bit of relief needed to get him on the field.

"The doctor felt like it was as good as it looked and this will take care of it so we can get him in some games at [designated hitter]," Melvin said. "We'll see when the throwing comes along, but we certainly don't feel like this is a setback. It's actually probably the last thing to move forward at a better pace."

"I sure hope so," said Barton. "I feel like I've had enough setbacks. It's frustrating not being able to go out there."

Barton was out to 120 feet in his throwing program before soreness forced him back to 90 feet. Now, he'll have to start the whole process all over again.

Meanwhile, Brandon Allen and Kila Ka'aihue appear to be the favorites to land the everyday first-base job, with Chris Carter still considered a candidate. Allen put together a seven-RBI day on Sunday and collected another on Monday against the Cubs in Mesa, while Ka'aihue started at first in Phoenix for a matchup with the visiting Angels, going 0-for-4.

Sore shoulder shouldn't limit Rosales' bench bid

PHOENIX -- Manager Bob Melvin revealed Monday that Adam Rosales had yet to appear in a Cactus League game because of shoulder soreness that surfaced last week.

Rosales fell on his left shoulder during a series of running drills and has since been limited to baseball activity. However, Melvin was set to play him on defense only in Monday's game against the Angels in Phoenix and, barring any further setbacks, he should be able to get enough at-bats this spring to still be considered for a bench spot on the club's Opening Day roster.

"It's getting better," Rosales said. "It's just a little frustrating because I've been itching to get out there."

Melvin is hopeful Rosales can avoid a spring similar to the one he endured last year, when he was on the mend from foot surgery. He began the season on the disabled list and never found a groove at the plate once being reinstated in June, ultimately hitting just .098 in 24 games over three stints with the A's. Much of those struggles, Melvin believes, stemmed from Rosales' inability to get the needed spring at-bats.

"[Utility players] are no more ready during the course of the season to play than when they come out of spring," he said. "Last year that wasn't the case for Rosales, and it set him back, and I think, to an extent, it affected his whole season."

Rosales is considered a strong possibility to break camp on the roster, but the A's also like the versatility Eric Sogard brings to the club. Sogard, who can play all over the infield, represents something of a dark horse for the third-base job should Josh Donaldson fail to win it. Should Melvin go that way, Donaldson could make the team as a utility guy over Rosales because of his ability to catch, too.

Athletics bring in Prieto to help Cespedes

PHOENIX -- A familiar face was brought in to A's camp on Monday to help out a new one.

Former A's pitcher Ariel Prieto, who is the pitching coach at Oakland's short-season Class A affiliate, is on hand to aid Cuban outfielder Yoenis Cespedes in his transition to the big leagues. There's a strong chance Prieto sticks around in that capacity on a full-time basis, leaving behind his Minor League role.

The A's have yet to announce anything regarding the situation.

Like Cespedes, Prieto himself defected from Cuba, and in 1995 the A's made him their first-round Draft pick. The highly touted pitcher went just 15-24 with a 4.85 ERA in his six-year big league career, five of which were spent in Oakland.

Worth noting

• Right-hander Brad Peacock was greeted by quite the task in his spring debut Monday, as the visiting Angels ran out the majority of their regulars in a potent lineup that includes Albert Pujols, who knocked an RBI double in his first at-bat.

Peacock called facing Pujols for the first time "pretty cool" and said he tried not to look at him when he was in the box. In 1 2/3 innings, the righty was tagged for four runs on four hits with one walk and one strikeout.

Manager Bob Melvin, though, believes the numbers don't tell the whole story and said Peacock got squeezed by home-plate umpire Derryl Cousins more than once and, as a result, had to throw more balls down the middle of the plate than he'd prefer. He considers Peacock to be in the mix for a rotation spot.

• Though right-hander Grant Balfour gave up his third home run of the spring and walked three in two-thirds of an inning on Monday, Melvin said "it will take a lot more of those outings for me to worry about him." Balfour has admittedly been known to fare poorly during spring games.

Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.