MESA, Ariz. -- Cubs shortstop prospect Javier Baez is starting to get into the swing of things in extended spring camp.

He's not the only one.

Baez is one of close to 80 prospects training or rehabbing at the club's complex in Arizona. Players working out in Mesa will eventually end up playing for the club in the Dominican Summer League, the Arizona Rookie League, Class A short-season Boise or Class A Peoria.

It's unclear where Baez will start the season.

"Right now, I'm working on my offense," said Baez, the club's first-round selection in the 2011 First-Year Player Draft, No. 9 overall. "We are working to make my swing smoother and put me in a position that gives me more control. It's not just about swinging as hard as you can."

Baez, ranked No. 3 on the Cubs Top 20 Prospects list, shined as an amateur at Arlington Country Day School in Jacksonville, Fla., and was the fourth position player taken in last year's Draft. He hit .771 with 22 home runs, 20 doubles and six triples in his senior year. He stole 28 bases and struck out only three times while leading his school to the National Association of Christian Athletics championship.

And while Baez isn't a prepster anymore, school is still in session.

"It's little different working out and playing every day, but I'm getting used to it," Baez said. "Here, you play in the daytime, and that's new, too. But it's been a lot of fun."

Extended spring camp has also been a lot of work.

"It's an opportunity to get quality instruction and work," said Oneri Fleita, the club's vice president of player personnel. "With Baez, just like every player, we hope to develop a foundation and give them the opportunity to learn and develop a routine every day. This is the first step in their careers."

Fellow prospects such as pitcher Gerardo Concepcion, first baseman Dan Vogelbach, Jemier Candelario (third base), Geoskar Amaya (second base), and outfielders Shawon Dunston Jr. and Trevor Gretzky have also impressed in Arizona.

Gretzky, drafted in the seventh round by the Cubs last summer, had shoulder surgery during the offseason and continues to make progress with his throwing program. He has been taking batting practice and is participating in fielding drills at first base. He hopes to see action in the outfield in the next few weeks.

"Rehab is going well," said Gretzky, son of the Hall of Fame hockey player. "I had my first game [Tuesday], and I hit the ball hard a couple of times, so that felt good."

Concepcion, who signed a multiyear deal with the Cubs in February, was named Rookie of the Year in the Cuban Serie Nacional in 2010-11, after posting a 10-3 record and a 3.36 ERA in 21 games with Industriales de la Habana. He defected from Cuba in June during the World Port Tournament in the Netherlands.

"He got to Spring Training late. He was a little behind, and right now, he's catching up," Fleita said. "He's having the Spring Training that he missed. Once we get him built up, he'll join one of the clubs."

In addition, Mark Johnson, the manager at Boise, Rookie League manager Bobby Mitchell and short-season Minor League hitting coordinator Tom Beyers, former Major League first baseman Bill Buckner, the hitting coach at Boise, have been working closely with the prospects in Arizona.

Buckner last coached in the big leagues for the White Sox in the mid-1990s. Like Baez, he is also getting back into the swing of things.

"As an organization, we are very fortunate to have someone who has nearly 3,000 hits and years of experience," Fleita said. "To know that our players have an opportunity to pick his brain and be associated with him day-in and day-out only adds to that very foundation we are trying to build. He's a great guy, and we are very happy to know Bill Buckner is a Chicago Cub."