NFL diehards are calling offside on the league over players’ anthem protests, a new poll has found.

Thirty percent of self-described “fans of the NFL” say they are watching less football this season, and more than half blame players protesting racism by kneeling during the national anthem, according to the Seton Hall Sports Poll, conducted by The Sharkey Institute.

Of those watching fewer games, 52 percent said it was because they disagreed with the protests.

Six percent said they were boycotting games in solidarity with kneeling players.

The issue has become a flashpoint for Americans since President Trump said on Sept. 22 that NFL team owners should fire “son of a bitch” anthem protesters, and then spent the weekend waging war against the league in a flurry of tweets.

On that front, 28 percent of fans said they agreed with the president, while 55 percent said that they backed the league. The remaining 17 percent did not pick a side, the survey found.

Just 38 percent of fans said they actually support players who kneel, suggesting not all of the of the people backing the league against Trump actually like the players’ protests.

Across the line of scrimmage, 45 percent of NFL lovers reported they disapprove of the kneeling.

The controversy caused such an uproar that DirecTV allowed fans angered over the protests to cancel their “Sunday Ticket” NFL packages for a full refund — a first for the satellite provider.

The poll also found that NFL fans generally had stronger opinions about the players’ antics — people who did not identify as diehards tended to respond “don’t know” or “no opinion” more often when asked about political aspects of the game.

Among football fans, just 1 percent said they were watching less because they were bothered by the increase in reports about the dangers of head injuries that players face.

The study, conducted by the Sharkey Institute on behalf of Seton Hall, polled 845 US adults between Sept. 25 and 27 on land lines and cellphones. The estimated margin of error is 3.8 percentage points.