Sosa, Bonds prepare to reshuffle list of all-time sluggers

In a corner of the Chicago Cubs' Cactus League clubhouse, Sammy Sosa spends a rare moment in solitude – away from packs of aggressive autograph hounds and reporters – crooning to himself as a boom box pulses with his favorite Latin salsa.

Outside, the capacity crowd at HoHoKam Stadium waits for the strapping, muscular slugger to emerge and rule over home plate.

Wrapping the handle of his mighty maple bat with white tape to secure a better grip, Mr. Sosa knows too well that fans have one expectation: To see the smily Dominican swing for the fence every time he digs in.

On this day at a pre-season showdown in Arizona, Sosa is scheduled to duel with last year's major-league home run champion, Barry Bonds of the San Francisco Giants.

Not since the spring of 1999, after Sosa went head-to-head with Mark McGwire to break Roger Maris's legendary home-run mark, which stood for four decades, has there been a bigger rivalry building among millionaire baseball players.

As opening-day nears, Bonds and Sosa are considered the leading contenders for breaking the single-season record of 73 round trippers – a mark notched by Bonds only a few months ago.

But for Bonds, in particular, the first few weeks of the season offer their own intrigue. He is now just seven homers shy of passing Hall-of-Famer Harmon Killebrew to become sixth on the all-time list. And not far beyond Killebrew's career total of 573 home runs lies the recently retired McGwire, in fifth place, and Frank Robinson in fourth. Bonds (and Sosa, too) can even hope to someday pass Willie Mays, then Babe Ruth, and perhaps Hank Aaron – the king of swing with 755 career homers.

Catching Mr. Killebrew, the long-time Minnesota Twin who retired in 1975, represents more than an abstract statistical achievement. For many ardent baseball watchers, it symbolizes a study in contrasts between the legendary power hitters of old and the new generation of beefy barrel-chested batters, whose upper body strength is changing the dynamic of the summer game.

Compared with Mr. Killebrew, who was known for his working-class lumberjack frame, Sosa, Bonds and others are like marbled Greek statues whose physiques are custom-shaped by Nautilus.

Killebrew laughs at how fitness attitudes have evolved from the days when he kept in shape in the off-season by hauling around 10-gallon milk jugs for a local dairy. "I was under strict orders from the team trainer not to lift weights, because he thought it would make me muscle-bound and unable to be limber when I swing," Killebrew recalls.

After meeting McGwire a few years ago, Killebrew remarked: "Mark McGwire's arms are bigger than my legs."

This season, the Cubs have amassed perhaps the premier one-two-three punch of power hitters in the big leagues with Sosa, Fred McGriff, and Moises Alou who, during a recent batting practice, pounded a fusillade of 400-foot homers into the palm trees on the other side of the center-field fence.

When McGriff is asked to size up the difference between his era and home-run hitters of the past, he answers simply: "Strength."

But Mr. Killebrew believes a combination of forces are at work that has turned modern baseball into a power hitter's dream, threatening records that previously were thought beyond reach. "I'm not trying to diminish the level of athleticism that exists today, because there obviously are some great ballplayers," he says. "But the environment is different. When Fred McGriff says that players are stronger, does he mean that Mickey Mantle wasn't strong?"

It's true, Killebrew notes, players are better conditioned due to sophisticated, year-round work-out regimens. But he says long-time scholars of the game also point to the addition of more teams, which has diluted the pitching talent; newer stadiums with smaller outfields; a more hitter-friendly strike zone adhered to by umpires; and better bats and improvements in baseballs that have fueled a surge in home runs that is on the upswing.

Decades ago, every team had only a few long-ball hitters, who were well-known to opposing pitchers, making it easier for hurlers to work around them. "Today, with stronger players across the board you have to be careful," says Cubs starting pitcher Kerry Wood. "A guy who's 5-foot, 9-inches and bats eighth in the lineup can rip one out. Personally, I'd rather face someone who's swinging for the fence on every pitch."

As statisticians note, there might be some wisdom in the hypothesis that sluggers of Killebrew's era were more discriminating – they had a significantly lower home-run-to-strikeout ratio. Sosa, for example, is close to the Cubs' home record of 512 but already holds the club record for strikeouts, with 1,395.

Fans don't seem to mind, though. In the desert setting where many major-league teams gather for workouts, the rivalry between Sosa and Bonds has taken on a tabloid flavor as the two exchange playful jabs in the press.

In the end, Bonds is a no-show for this game, claiming to need rest. Sosa, however, is in great form. Although he doesn't knock any homers today, he sends several fastballs rocketing deep into the outfield. He's seeing the ball well and making good contact, he says.

Six months from now, when he and Mr. Bonds find themselves in the middle of a home-run derby, fans will be waiting for souvenirs in the faraway bleachers.