The Supreme Court will hear the case of Joe Kennedy, a Washington state high school football coach who was placed on leave six years ago for praying after games.
Kennedy told The New York Times he made a promise to God when he became a coach.
He said that he would give you the glory after every game, win or lose, and that the setting mattered.
Kennedy would kneel at the middle of the field after games and pray.
He sued the school district for violating his First Amendment rights by telling him he couldn't pray.
The lawyers for the school district argued that if Kennedy prayed alone and separately from students or if he came back after students left to pray, it was not an issue because he was not endorsing religion.
The school district said in a Supreme Court brief that some residents who didn't approve of praying on the field have kept quiet because of the attention the issue has gotten.
The president of Americans United for Separation of Church and State told The Times that the concern is that when the coach goes to the 50-yard line to pray, there's pressure on kids to join.
Kennedy has said he never cared if students joined, but one student said they did so because he was worried he would lose playing time.
The Supreme Court has a history of rejecting prayer in public schools, and Kennedy has lost many times in court.
The court ruled in 2000 that student-led prayers at high school football games also violated the first amendment because they force those who are there to participate in religious worship.
Some sitting conservative justices have expressed some concern over how the case was decided.
Laser told The AP that if the Supreme Court rules in favor of Kennedy, teachers and coaches could force students to pray in every public school classroom across the country.