The Rookie has a starring role in Cubs' quest for a championship

There's the Import, Kosuke Fukudome, the SI cover boy and the new toast of the town. There's the Ace, Carlos Zambrano, who has finally learned to harness his emotions and is off to his best start since 2004. There's the Skipper, Lou Piniella, the celebrity manager whose arrival a year ago fueled the resurrection of the franchise. There are a number of reasons why the Chicago Cubs, owners of the best run differential in baseball, are the best team in the National League today and a threat -- yes, really -- to end their century-long World Series drought. But the biggest reason? It's the Rookie, Geovany Soto.

"He's the difference maker," says one National League executive. "Not just with the bat he gives them. He's stabilized the pitching staff."

Says a scout, "Catchers who do it all are such a scarce commodity in the game. He doesn't play or carry himself like someone who's never played a full season. He's going to be the best catcher in the game for a number of seasons to come."

Only one rookie in history -- Andy Etchebarren for the '66 Orioles -- has been a fulltime catcher on a World Series champ. Now here is Soto, the 25-year-old from San Juan, Puerto Rico, who give the faithful reason to believe that a trip to the Fall Classic is possible. Soto, who played a total of 30 major league games the previous three seasons combined, makes this year's North Siders the most complete Cubs team in years -- yes, he was first or second among major league catchers in home runs, slugging, OPS and RBIs, but his biggest contribution has been the plate discipline he's brought to the once free-swinging Cubs lineup. Over the last five years Chicago has ranked 14th, 14th, 16th, 16th and 15th in walks. Thanks to the additions of Soto (39 walks) and Fukudome, the Cubs have leaped to first in the majors in free passes.

"This year it's a different lineup-- a more disciplined lineup," says Reds pitcher Bronson Arroyo. "Maybe [Soto and Fukudome's] discipline has rubbed off on the others."

Just as impressive have been what Soto has done behind the plate. He has learned to tame the combustible Zambrano -- "He understands me, knows how to kick me in the ass when he has to but also knows how to calm me down when I'm too hot," says El Toro -- and guided youngsters like 22-year-old Sean Gallagher, who has ably filled in for the struggling Rich Hill in the rotation. "We sit down before games and go through every batter's strengths and weaknesses," says Gallagher. "He prepares for every game like it's an exam."

Only a year ago Soto was a middling minor league prospect with a career batting average barely north of .260. Entering last season he had 26 career home runs over six minor league seasons. But then Soto exploded: In 2007 he led the minors in batting average by a catcher (.353) and overall slugging percentage (.652), won the Triple-A Pacific Coast League MVP award and was the Cubs' minor league player of the year.

The difference? "I changed what I ate," says Soto. He went on the Kerry Wood Diet, trading junk food for premade organic meals, and dropped over 20 pounds. "He asked me about it," says Wood. "It was something I did and lost a lot of weight but felt stronger. I think he feels the same way." Indeed, Soto gained a step and was suddenly able to turn around inside fastballs that would blow by him in the past. Now he's also demonstrating an ability to drive pitches on the outside of the plate the other way. Says the scout, "He's a complete hitter -- I project him down the road as a .300 hitter with the pop to hit 25 home runs every season."

But forget about future projections. The Cubs are the best team in the National League at this season's midway point, and the Rookie is ready to lead them all the way through October.