PHOENIX -- Chris Carter and Michael Taylor have lockers next to each other inside the Phoenix Municipal Stadium clubhouse.

It is difficult to forecast when they will be side by side in the A's batting order.

The team's two most talked-about prospects, Carter and Taylor were pegged as future cornerstones of the offense at the time they were acquired in separate trades. But neither outfielder is forcing his way into Oakland's plans as quickly as anticipated.

Carter, 24, was obtained from Arizona in the Dan Haren trade of December 2007 and showed flashes of his potential during his brief big league exposure last season. But he also struggled enough to convince the A's he needs more seasoning at Triple-A Sacramento.

Taylor, who came over from Toronto in December 2009 for infielder Brett Wallace, hit just .272 for Sacramento and showed little power. By all indications, Taylor, 25, is behind Carter in terms of big league readiness.

General manager Billy Beane was asked if he expected both prospects to be further along in their development.

"Not necessarily," Beane said. "I think, quite frankly, Chris has moved very quickly, given where he was when we acquired him and where he is now. In Michael's case, he finished (the 2009 season) in Triple-A and did quite well. So we know he's capable of playing at that level.

"The fact of the matter is, they're both right there, and they're really just a phone call away."

The A's are preaching patience with both, but there will be holes to fill beyond 2011. None of this year's projected starting outfielders -- Coco Crisp, David DeJesus and Josh Willingham -- are signed beyond this season.

Designated hitter Hideki Matsui is on a one-year contract.

Unless they re-sign all of them, the A's will be in need of offensive reinforcements, and they prefer those would come from within the organization.

"As far as their age is concerned, (2011) is an important year," said a major league scout who requested anonymity. "I wouldn't say it's make or break, but they have to prove it out on the field."

Carter endured an Oakland record 0-for-33 streak to begin his big league career in August. He was sent back to Sacramento, but after being recalled Sept. 14, he went 13 for 38 (.342) with three homers and seven RBIs over his final 13 games.

The A's point to that trend throughout Carter's career -- he has struggled initially at each level before making the adjustment.

Carter hit .337 with 24 homers and 101 RBIs for Double-A Midland in 2009, but that high average might have been deceptive. Scouts consider him a pure power hitter who will always rack up high strikeout totals.

Carter said he tries to take cues from hitters such as Albert Pujols and Alex Rodriguez.

"Watching Pujols and A-Rod hit, it looks like they have a plan," Carter said. "They have a zone, and they're not waiting for anything else."

Taylor had just six homers and 78 RBIs for Sacramento in 127 games, missing a good chunk of time with a calf injury.

"It really felt like a long year," Taylor said. "But in some ways it's kind of the season I'm most proud of because I didn't crack."

Despite Taylor's 6-foot-5, 256-pound frame, the above-mentioned scout said Taylor is suited to be a line-drive hitter rather than a home run machine.

He received swing advice from all directions last season.

"We all had ideas about how to do things," A's director of player development Keith Lieppman said. "In fact, he probably took on too many ideas."

Taylor also worked with Dodgers manager Don Mattingly -- his manager during the Arizona Fall League -- who helped him identify one area on which to focus.

"I had a stop in my swing," he said. "Some of it came about from working on mechanics so much that you lose your rhythm. Right now I'm trying to be real rhythmic."

The A's appear set with five outfielders -- Willingham, DeJesus, Crisp, Conor Jackson and Ryan Sweeney. But manager Bob Geren pointed out that Carter or Taylor could have his number called at any time.

"It's a crowded outfield situation," Geren said. "Then again, not one of those five guys (stayed healthy) last season. Anything can happen, and everybody's got to be ready."