Hit a home run at Comerica park with the Tigers.
Hit a home run at Midway Park.

At the Title Screen or the Main Menu press Y, X, R to unlock all Fantasy Teams and

Fantasy Stadiums.
Enter these codes at the versus screen:

Unlimited Turbo: X, X, X, X, Y, Y, Y, Y, B, B, B, B, DOWN
Softball Mode: X, X, Y, Y, Y, Y, B, B, DOWN.
Ball Is Rubber: X, X, Y, Y, Y, Y, B, B, UP.
Max Out Speed: B, B, B, LEFT.
More Time After Each Play: X, Y, Y, B, B, B, LEFT.
Big Heads: X, X, RIGHT.
Tiny Heads: X, X, LEFT.
Max Out Batting: X, X, X, LEFT.
Max Out Power: Y, Y, Y, LEFT.

The following is a list of Fantasy teams and the real teams that each corresponds to.

Lions: Houston
Horse: Philadelphia
Pinto: Atlanta
Eagles: St. Louis
Gladiators: Boston
Bobble Head: Toronto
Dolphins: Florida
Scorpion: Arizona
Sub-Zero: Seattle
Evil Clowns: NY Yankees
Minotaur: San Francisco
Alien: Minnesota
Casey: Chicago Cubs