Backyard Baseball Cheat Codes for Playstation 2

Better bats:
To get a special bat (in any mode except tee-ball) you must get a double play. You can walk a man. When the other player comes up, he might hit a single. Note: Get a fast pitcher to run to first and tag the player out. Note: Sometimes you may strike out the person or not get him if you have two outs.
Submitted by: Codec

Abner Dubbleplay:
Earn all certificates to unlock Abner Dubbleplay as a player.

Home Run Derby:
Note: You have to be fast. Choose two people and select a third person immediately before the screen changes. This will help you get more hits and home runs.

Hitting power-ups
To get two hitting power-ups, get the bases loaded. An easy way to do this is to get some fast runners and have them all bunt. Then, get your power hitter in there and hit the ball over the fence. As soon as the last person touches the plate, you will feel a rumble that indicates you got the power-ups.

Aquadome
Hit a homerun into the pool at Steele Stadium, into the swamp at Gator Flats, and into the lake at Frasier Field. The Aquadome stadium should now be unlocked.

Barry Deejay
Have a saved game file from Backyard Basketball on your memory card.

Abner Dubbleplay
Earn all twenty certificates to unlock Abner Dubbleplay as a player.

Derek Jeter
Execute two double plays in a single game in season mode.

Greg Maddux
Win 20 games in season mode. Note: Try playing a 32 game season.

Mike Piazza
Hit a grand slam in season mode.

Mr Clanky
Complete Clanky's Coaching Box.

Pedro Martinez
Throw a shutout in season mode.

Randy Johnson
Get 75 career strikeouts, which includes the playoffs. If you have any other pitcher, put him in. He does not have that good Running, Contact or Defense status, but is a very good pitcher.

Shawn Green
Hit the ball to gain a base 60 times in season mode.

Certificate list
The certificates required to unlock Abner Dubbleplay are as follows:
Submitted by: Codec

3 Homerun Game
Grand Slam
Hit The Cycle
10 Strikeout Game
3 Stolen Base Game
Winning Pitcher
Threw A No Hitter
Threw A Shutout
5 RBI Game
MVP Of Game
10 Career Hits
30 Career Hits
80 Career Hits
5 Career Homeruns
15 Career Homeruns
30 Career Homeruns
25 Strikeouts
75 Strikeouts
150 Strikeouts
10 Pitching Wins
20 Pitching Wins
30 Pitching Wins
10 Stolen Bases
25 Stolen Bases
50 Stolen Bases