"If they tell other students to support their team, why can't I support mine?" Brandon Frost, 17, told The Associated Press. The senior at Maurepas High School moved three years ago from Indianapolis to the rural town 30 miles from Baton Rouge.
A Livingston Parish School Board member said Frost wasn't sent home, but was told he couldn't wear the blue jersey at school. Keith Martin, whose district includes Maurepas, said the school uniform had been relaxed only for black and gold.
He said he planned to ask school system attorneys whether that violated Frost's right to free speech, as the American Civil Liberties Union of Louisiana contends.
State ACLU director Marjorie Esman sent a letter to Principal Steven Vampran, asking him to wipe Frost's record of any discipline stemming from the incident.
Vampran declined to comment.
Martin said he had talked with both Vampran and Frost's father, Larry Frost.
"I think we got things worked out," Martin said.
According to Martin, a friend of Brandon Frost's had asked Vampran on Thursday whether Brandon could wear a Colts jersey, and had been told "no."
During a class on Thursday, Frost said, he talked about his plans to wear his jersey rather than Saints colors. He said the teacher warned him he'd get in trouble.
Larry Frost said he didn't know about that when Brandon asked Thursday whether he could wear the jersey. He said he told his son to come home if he was hassled too much.
The Colts and Saints play Sunday in the Super Bowl, and emotions have run high in Louisiana as fans celebrate the first Super Bowl appearance for the beleaguered franchise.
Brandon Frost said Vampran called him out of his first class Friday and told him, "I don't recall saying you could wear a Colts jersey on Black-and-Gold Day."
He said he told the principal that his father had given him permission to go home if it was a problem.
"He started to get angry with me," Frost said. "I thought I remember him saying, 'If you like Indiana so much, why don't you go back?"'
Vampran has acknowledged that he should not have said that, Martin said. He said no one sent Frost home - but no one kept him from leaving rather than changing shirts.
Larry Frost said he called the ACLU rather than the school because he was too angry.
"Louisiana would be proud of him anyway," Larry Frost said. "He wore Joseph Addai's jersey."
The Colts running back is a graduate of Louisiana State University.