(Reuters) - Most of the National Football League’s Houston Texans team knelt in protest as the national anthem was played for Sunday’s game in Seattle, an apparent rebuke of team owner Bob McNair for his remark about “inmates running the prison.”

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Backlash over the comment rekindled a national debate over NFL players, mostly African-Americans, who have broken with tradition by taking a knee or raising their fists during “The “Star-Spangled Banner” to protest racial bias in the U.S. criminal justice system.

U.S President Donald Trump escalated the controversy in September when he suggested owners should fire any “son of a bitch” who refused to stand for the anthem.

The opening ceremonies of the Texans’ late-afternoon game against the Seattle Seahawks were not broadcast live on CBS. But the network’s “Post Game Show” aired a brief clip of Houston’s players collectively taking a knee with arms linked along the sideline during the national anthem.

According to the Seattle Times, nine of the Texans stood for the anthem, but the rest were kneeling or seated. The New York Times said about 40 players in all refused to stand. It marked the first time that the Texans as a team knelt in protest during the national anthem, the Houston Chronicle reported.

The players were widely reported to have been planning an en masse demonstration against McNair over his choice of words.

“We can’t have the inmates running the prison,” McNair was quoted as saying during a recent meeting with league executives and owners, exhorting them to consider how the kneeling protests could hurt the NFL’s bottom line.

The comment, first disclosed in an article published online by ESPN The Magazine on Friday, sparked immediate outrage from players, fans and supporters of the anthem protests as the NFL sought to tamp down the issue.

In a public apology after meeting on Saturday with the players, McNair, 79, a billionaire who like many NFL owners contributed to Trump’s presidential campaign, insisted that his “inmates” metaphor had been misinterpreted.

“I was not referring to our players when I made a very regretful comment during the owners meeting last week,” he said. “I was referring to the relationship between the league office and team owners and how they have been making significant strategic decisions affecting our league without adequate input from ownership over the past few years.”

He added: “I am truly sorry to the players for how this has impacted them and the perception that it has created for me which could not be further from the truth.”

Asked after Sunday’s 41-38 loss in Seattle how the Texans players’ meeting a day earlier went with McNair, Houston offensive tackle Duane Brown told the Chronicle, “not too well.”

The newspaper said McNair did not attend Sunday’s away game due to health issues.

The national anthem protests began in 2016 when Colin Kaepernick, then a San Francisco 49ers quarterback, began sitting and later kneeling during the anthem to call attention to police shootings of unarmed black men in the United States.

Kaepernick was not signed by any team after becoming a free agent following the 2016 season. He has filed a claim of illegal collusion against the league’s owners.