SCOTTSDALE, Ariz. -- Nick Noonan hit a wall. Once a top prospect on the fast track, he had a miserable year at Double-A Richmond that included a stubborn hamstring injury and a badly bruised psyche.

He went to the Giants' instructional league in September determined to remake his swing. And he knew what template to use.

"I watched Brandon Belt," Noonan said. "I raised my hands. I opened up my stance. I started tucking my front knee to get my weight back. It's 180 degrees for me. I think I'll be able to drive the ball this year."

How did this happen overnight? Weren't the Giants choking through a two-decade drought of developing big league hitters? Now they have Buster Posey, the 2010 National League Rookie of the Year. And suddenly, they have Belt, too -- an apparent left-handed Buster with power to all fields, a mastery of the strike zone and an outside shot to make his major league debut on opening day.

Posey and Belt have the look

of perennial impact players. They're already making their presence felt in how the Giants are instructing and evaluating their young hitters.

They aren't breaking the mold. They're creating one.

"When we compare Belt to Posey, it's not because he burst on the scene like Posey did," Giants general manager Brian Sabean said. "It's that the swing is very similar. Fundamentally, the bat stays in the zone a long time. They're able to track and lay off pitches, and they have a way to get the fat part of the bat on the ball, as well as go deep in the count, take a walk, be a two-strike hitter. Hit with men on base.

"Posey made professional adjustments almost overnight and was able to get better even as he went to higher levels. Same thing (with Belt). The statistics are obvious, but the more you watch him, you realize he's ahead of most hitters."

Until recently, it hasn't been hard for a hitter to get ahead in the Giants system. It's the biggest criticism of Sabean's 15-year tenure: In all that time, the Giants haven't drafted and developed a single position player to represent the club as an All-Star. The dry spell mostly had to do with poor draft position, including an ownership directive to punt the occasional pick and steer bonus savings to the major league payroll during the Barry Bonds era.

The few decent hitting prospects to enter the Giants system -- Todd Linden, Dan Ortmeier, Lance Niekro, etc. -- all seemed to wash out, collecting like driftwood in a tide pool.

Posey, the fifth overall pick in 2008, illustrated the value of drafting high. And Belt is poised to represent a triumph for a rebounding player development system.

In just one season, farm director Fred Stanley and hitting coordinator Bob Mariano helped Belt transform himself from a lightly regarded college senior with a crouched, closed stance and metal-bat swing to a hard-hitting force who flew through the system.

"When I got to (instructional league), I knew something would change with my stance," said Belt, a fifth-round pick in 2009 from the University of Texas. "I wasn't sure what was going to happen. Bobby Mariano worked with me every day, raised my hands, opened me up a little bit. That completely changed my entire world right there. I was able to see the ball better. I was able to pull the ball, hit it the other way -- pretty much everything.

"They're doing that with everybody now."

Mariano uses a subscriber-based video system that can freeze-frame a young player's swing and compare it, point by point, to major league hitters. It's a way to persuade struggling prospects to change a hitting style that might have served them well in college or high school.

Mariano said he'll break down tape of All-Stars such as Chase Utley, Robinson Cano and Joey Votto to demonstrate "the importance of what we describe as being 'short to long.' Keep that barrel in the zone a little longer so you don't have to be perfect."

It's a valuable tool. No matter how good a piece of advice might be, it won't do any good if the player doesn't fully buy into it.

Belt bought in from day one. And now Mariano has an even better visual aid to show the kids on the farm.

He has Belt and Posey right in front of him.

"Brandon Belt has the best pitch recognition I've seen in my six years here," Mariano said. "Just great aptitude. He's like Buster in that he's able to make adjustments from pitch to pitch, from at-bat to at-bat. He sets up like Posey. The hands and center of gravity are the same."

Belt's first home run in a Giants uniform told the story. Tim Dillard, a sidearm right-hander for the Milwaukee Brewers, threw Belt a changeup. Belt took it for a strike. Dillard went back to the same pitch. Belt crushed it over the right-field party deck.

That was Friday afternoon. Later that night, in a split-squad game against the Dodgers, Posey hit an opposite-field home run.

Can Belt keep up with the Posey comparisons?

"Oh man, he did something just outstanding last year," said Belt, a quiet Texan who turns 23 next month. "I don't know anybody who could live up to that. He walked into the big leagues as a 23-year-old, took care of the pitching staff and hit like it was no big deal. I hope to follow in his footsteps, but that might be hard to do because he was so awesome."

Last year, Sabean kept Posey at Triple-A Fresno for nearly two months to ensure his catching skills were ready for the big leagues. Sabean has no concerns with Belt's plus defensive ability at first base, yet the GM would like to see his top prospect get more exposure in the Pacific Coast League beyond the 13 games he played for Fresno at the end of last season.

Sabean is open-minded to letting Belt crack the opening-day lineup, though. So is manager Bruce Bochy. It's quite a statement for two seasoned baseball men who are reputed to trust veterans over kids.

Perhaps Posey and Belt are changing that dynamic, too. If the tides are truly changing, you can't hold them back.