The 1998 Major League Baseball season ended with the New York Yankees sweeping the San Diego Padres in the World Series, after they had won a then AL record 114 regular season games. The Yankees finished with 125 wins for the season (regular season and playoffs combined), which remains the MLB record. The 1998 season was marked by MLB’s expansion to 30 teams (16 in the NL, 14 in the AL), with two new teams–the Arizona Diamondbacks in the National League, and the Tampa Bay Devil Rays in the American League–added. To keep the leagues with even numbers of teams while allowing both leagues to have a new team, the Milwaukee Brewers were moved from the American League Central Division to the National League Central Division. The Detroit Tigers were shifted from the American League East to the American League Central, while the Devil Rays were added to the American League East. The Diamondbacks were added to the National League West, making the NL have more teams than the AL for the first time (this arrangement would last until the end of the 2012 season, when the Houston Astros moved from the National to the American League for 2013, giving each league 15 teams). The biggest story of the season was the historic chase of the single-season home run record held at the time by Roger Maris. Initially, the St. Louis Cardinals' Mark McGwire and Ken Griffey Jr. of the Seattle Mariners started the season on a pace to both break Maris' record. In June, the chase was joined by the Chicago Cubs' Sammy Sosa, who broke the decades-old record of Rudy York for most home runs in a calendar month with 20 that month. Eventually, Griffey fell off the record pace, but still ended with 56 homers. Both McGwire and Sosa broke the record in September, with McGwire ultimately finishing with 70 homers to Sosa's 66. McGwire's record would last only three years, with Barry Bonds hitting 73 in 2001. The 1998 season was also the first in MLB history with four players hitting 50 or more homers, with Greg Vaughn of the San Diego Padres hitting 50. In a postscript to the record chase, both McGwire and Sosa have since been widely accused of having used performance-enhancing drugs during that period, and McGwire would admit in 2010 that he had used steroids during the record-setting season. The defending World Series champions Florida Marlins finished last in the NL East Division at 54–108, making it the first, and only, time that a team went from winning the World Series one year to finishing with 100 or more losses and last in their division the following year.

New commissioner

On July 9, 1998, Major League Baseball Executive Council chairman Bud Selig officially became the 9th commissioner of baseball, though he had been the de facto commissioner for nearly 6 years. During that time, the owners had tried to find a replacement for previous commissioner Fay Vincent who was forced to step down by the owners towards the end of 1992 season mainly due to the lockout he intervened in during the 1990 season.

Standings

American League

National League

Postseason

This was the first season in which teams were seeded by their respective win–loss record within their respective leagues.

Bracket

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Awards and honors

Other awards

Player of the Month

Pitcher of the Month

MLB statistical leaders

1 American League Triple Crown pitching winner

Managers

American League

National League

Home field attendance and payroll

Television coverage

This was the third season under the five-year rights agreements with ESPN, Fox, and NBC. ESPN continued to air Sunday Night Baseball and Wednesday Night Baseball. Fox's coverage included Fox Saturday Baseball broadcasts, Thursday night games on Fox Sports Net, and Saturday primetime games on FX. NBC aired the All-Star Game. During the postseason, ESPN, Fox, and NBC split the four Division Series. NBC then televised the American League Championship Series while Fox aired both the National League Championship Series and the World Series.

Events

January–March

April–June

July–September

October–December