WASHINGTON • LeBron James is not sure why the National Football League (NFL) is losing US television viewers while the National Basketball Association (NBA) and Major League Baseball (MLB) enjoy strong ratings, but he warns the fun factor is dwindling.

The Cleveland Cavaliers superstar, speaking to reporters after a workout on Monday, said he enjoyed seeing his favourite NFL team, the Dallas Cowboys, win 35-10 at Cleveland on Sunday.

But he noted how several top NFL players have said the NFL is becoming the "No Fun League" and that this could be a factor in a ratings decline of about 18 or 19 per cent on Sundays and Thursdays and nearly 25 per cent on Mondays.

"I don't know the reason," James said. "I've heard some of the comments from some of the players about the game, that the fun part of it is kind of being taken away.

"I know when I played (American) football I played it for that reason, for the competition and for the fun of it. I've seen a couple of the main guys talk about how the game is not as (much) fun.

"You definitely don't want to take the fun away from the game. That's why we all fell in love with sports in general, to have fun with it."

The NFL fade comes as MLB's World Series enjoyed high ratings for the Chicago Cubs' first title run since 1908 while Cleveland missed out on its first crown since 1948 in a seven-game thriller that went into extra innings in the final game.

"Baseball, it needed a push and with the play-offs and the World Series this year, it definitely helped," James said. "Being at three of the World Series games, I think that history, them not being part of it and then being in it, that definitely helped."

Last season, the NBA had the highest ratings since Michael Jordan's Chicago Bulls were a 1990s dynasty as James and his team-mates made the greatest rally in NBA Finals history, recovering from 1-3 down to win a best-of-seven series for the crown just as the Cubs did.

"Our sport has done some great things over the last couple of years as far as the play-offs, especially in the Finals. We're just trying to continue to build our game," James said.

"To know you were part of a game that was something people wanted to watch, that's special. When they say it was the biggest ratings since Jordan in the Finals, that gives you a lot of pride."

AGENCE FRANCE-PRESSE