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.
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.
[2] 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.
[3][4] *Denotes walk-off 1 American League Triple Crown pitching winner This was the third season under the five-year rights agreements with ESPN, Fox, and NBC.