NBA Star Joe Johnson -- I Can't Go to Court ... The Nets Need Me to Win!!!

Brooklyn Nets guard Joe Johnson made it clear to a judge in Georgia -- postpone his baby mama trial until AFTER the NBA playoffs ... or risk angering the entire team's passionate fan base.

As TMZ first reported, Joe filed a suit against baby mama Shannon Beckton to be legally recognized as the father of their kid and share custody. The case was set to be heard between April 15 and May 5.

Like teammate Kris Humphries, that trial window was a BIG problem for Joe ... since the Nets made the playoffs and it could easily conflict with court times. To get the date moved, Joe explained to the judge he's a key member of the Nets and "a vital part of that team's success."

Joe also argued that his absence violate his contract (worth $126 million) and could seriously "harm" the Nets' championship dreams -- which would mean less cash for him and less cash for his kid.

The judge agreed and postponed the trial.