For a moment, it was pure joy for Marco Rocco of Haddonfield, N.J. Marco, 12, hit a majestic home run in a Little League tournament game against a team from Harrison, in the southern part of the state, on July 16. When the ball sailed over the fence, Marco did what many players in Major League Baseball do in similar moments, and what some players in the Little League World Series have done, too.

On his way to first base, he flipped his bat into the air to celebrate and continued his home run trot. The blast put his team up 8-0 and a step closer to the Little League World Series.

But throwing bats around small Little League fields is generally frowned upon by the leagues. Marco was ejected from the game, and, by rule, all ejections carry a one-game suspension for the next game, too. That meant Marco would be barred from playing in a showdown against Elmora Township scheduled for Thursday night, with a chance to win the New Jersey state Little League crown.

“He was completely confused and distraught,” his father, Joe Rocco, said.

So Mr. Rocco, who is a lawyer, asked a New Jersey court for a temporary restraining order, claiming that the international Little League organization, which runs the Little League World Series, was acting hypocritically because it actually promotes bat flips.

The judge, Robert G. Malestein in Gloucester County, N.J., agreed, and ruled on Thursday that Marco could play, writing in his decision, just hours before first pitch, that “Little League is enjoined from enforcing its suspension.”

“He said he wasn’t going to prevent a kid from playing because he did something that they promote all over their own social media,” Mr. Rocco said after the hearing.