KANSAS CITY — With every fastball he mashes over the wall or slices deep into the gap, Josh Reddick gets more comfortable in the big leagues –– flashing the kind of talent that should someday allow him to shed the label of prospect and become a major league player.

But for now, every toolsy taste of arm strength or bat speed is just that: a tease. Reddick is nowhere near ready for full-time major league duty, despite the singular moments of excellence.

"He's not ready to play every day in the big leagues," said manager Terry Francona. "He may not be ready to play every day in Triple-A. He's young; he's learning. But you can see what he can do. It's going to be a matter of learning, and getting consistent, things like that. He just needs to play more, and swing at good pitches. If he can do that? God, he can [accomplish] some things [as a big-league player]."

Reddick is in that enviable, yet frustrating position occupied by many top prospects in the later months of the year. He gets a chance to experience the big leagues perhaps before he is ready, knowing the whole time that it's almost certainly not permanent. And no matter how well he does here in the majors in September, or in spring training next season, he will probably still be sent to the minors to start 2010, turning those tools into major league-caliber skills at Triple-A Pawtucket.

He understands.

"I'm still learning and developing in ways that casual fans don't always see, learning little things that might only be obvious say, to the outfield coach," Reddick said.

It's a career path that sounds very familiar to one of his teammates, starter Clay Buchholz. Buchholz had the same combination of talent, early success, and comfort level –– and the organization kept him in the minors for the first half of this season Buchholz cautioned that once Reddick starts feeling like he's really ready, he should realize he probably isn't.

"When you think you're ready, you might not actually be ready," said Buchholz. "The guys in the front office, they've been doing it for a while, and they know when they see talent that's ready to play in the big leagues every day."

That's doubly important in the coming spring training, when a player like Reddick may feel like he can play his way onto the team. In reality, the organization may already have him ticketed for more development time.

"Even coming out of spring training, if you have a good spring training and don't make it out of spring training, you've just got to make sure you're ready whenever they do call on you. That was my visualization of [this] season," Buchholz said.

Reddick is only 22, and at 6-foor-2, 180 pounds, he's a lithe free swinger who knows he must improve his plate discipline and add more weight before he's ready for permanent duty.

Reddick was ranked as the system's fourth-best prospect by Baseball America before the season, and he showed why in spring training, hitting .500 and firing bullets with his powerful outfield arm. He skipped Triple-A and went all the way to the majors July 31, when injuries to outfielders Jason Bay and J.D. Drew gave him his unexpected opportunity.

The Georgia native impressed right away, going 5-for-16 in his first four games with three doubles and a homer –– and then promptly nosedived, getting only one hit in his next 16 major league at-bats before being sent back to the minors.

His first weeks in the majors drove home what his coaches had already told him: He needed to fine-tune his plate discipline and understanding of the strike zone. He found that the major-league zone was a little tighter than the one he'd seen in the minors, and that he needed to develop his ability to work counts. He'd take a pitch in the majors thinking it was a ball, and look back to learn otherwise.

"I'd turn around and the umpire would be making the strike sign, and I'd be like, ‘Well all right then,'" Reddick said.

He went to Pawtucket with those lessons in mind, and while the results weren't what he'd like he felt it was time well spent. He hit .127 with two triples and no home runs, but he was part of a bad lineup, and he walked six times in 71 at-bats, a decent pace for him.

"I know on paper it didn't look good," Reddick said, "but even down in Pawtucket I found myself taking more pitches, getting deeper into counts, and I was hitting the ball hard so I felt okay about it."

Reddick applied those lessons since returning to Boston. His second major-league stint is already going better than his first, and he's exhibiting slightly improved plate discipline coupled with the bat speed and spark he's always shown.

Friday, Reddick singled, and also worked an eight-pitch at-bat before striking out on a foul tip. Saturday night, he smashed a ball over the right-field fence in Camden Yards for a two-run homer, and almost hit another one out. Perhaps more importantly, he walked –– only the second time this season. After two pinch-hit outs in the last three games, Reddick has 4 hits in 12 at-bats during his second stretch in the bigs.

"He's a young, aggressive hitter that's trying to learn the strike zone, at a rapid pace. Whatever he does here isn't going to be the final," Francona said.

Reddick figures to be part of Boston's long-term plans, although exactly where he fits could develop over time. If Drew does not return after 2011, Reddick and his cannon arm should be ready to step in at right field in 2012. If Bay leaves in free agency this winter and the Sox sign a stopgap player instead of a long-term replacement, Reddick could get a shot at full-time play in 2011 or mid-2010.

dbarbari@projo.com