Its nose bloodied by scandal, the oldest of American professional team sports is ready to get back to doing what it does best — playing baseball.

The season begins tonight with the Boston Red Sox, finally freed from decades of futility after winning their first World Series since 1918, visiting their ancient rivals, the New York Yankees.

“Only fitting,” Boston first baseman Kevin Millar said. “It’s the greatest rivalry in sports.”

Monday afternoon, the sport’s attention will shift to Citizens Bank Park, where the Washington Nationals, reborn and renamed after barely surviving as the Montreal Expos, play their first game.

“It will be very special,” Nationals manager Frank Robinson said. “Anyone who tells you it’s not, something is wrong with them.”

These are Dickensian days for major league baseball.

Commissioner Bud Selig says the game is more popular than ever, and the numbers support his claim. Last season, more than 73 million fans attended games, the most in history. The average attendance — 30,401 — was the third-most ever. Revenues were more than $4 billion. Lucrative partnerships have recently been signed with XM Satellite Radio, General Motors and Home Depot.

And yet, as fans prepare to flock to ballparks for opening day, controversy and public skepticism hover over the sport because of a steroid scandal that has implicated big names.

The scandal has played out in a San Francisco federal investigation and led to a congressional hearing last month in which lawmakers roughed up subpoenaed players and officials while demanding that the sport be cleaned up.

Selig said his office was well on its way to doing that after finally winning the right to test players for steroids in collective bargaining. In 2003, the first year of testing, about 7 percent of tests were positive. Last year, between 1 percent and 2 percent were positive.

“The theory that steroid use is rampant in baseball is just wrong,” Selig said. “We’ve made enormous progress.”

Some players feel wronged by the actions of a handful.

“We’re in an era where, unfortunately, if you’re good, people are going to say, ‘He probably had enhancement,'” Phillies closer Billy Wagner said. “We’re all under the microscope.”

“We can speculate who did what until the cows come home, but that’s meaningless because there wasn’t a testing program,” Chicago Cubs general manager Jim Hendry said. “We have to move forward and let the policy work.”

The specter of steroids won’t go away quickly, not with San Francisco Giants slugger Barry Bonds climbing the home-run chart and closing in on two all-time greats.

Bonds is a seven-time most valuable player with 703 career homers, 258 coming in the last five seasons. Only Hank Aaron (755) and Babe Ruth (714) have more.

While steroids represent baseball’s seamy side, there is plenty to feel good about as opening day arrives.

The nation’s capital has a team for the first time since the Senators left in 1971.

Long-tortured Red Sox fans can boast about their team’s being defending world champion for the first time since the Wilson administration.

And the sport’s international flavor is powerful. Last season, Anaheim’s Vladimir Guerrero, a native of the Dominican Republic, won the American League’s Most Valuable Player Award. Seattle’s Ichiro Suzuki of Japan broke an 84-year-old record for hits in a season with 262. Minnesota’s Johan Santana became the first Venezuelan to win a Cy Young Award, and Quebec native Eric Gagne, the Los Angeles Dodgers closer, ran his record streak of consecutive saves to 84.