LeBron James is carrying the weight of an entire franchise on his back, but nobody seems to care if he’s getting tired.

Not even those on his team.

A weary James asked to take a breather for the first three minutes of the fourth quarter in Thursday’s Game 1 of the NBA Finals. When he came back into the game, he couldn’t save the Miami Heat, and they lost to the San Antonio Spurs 92-88.

James has been toting around the Heat all season with his all-around game and it’s been even more taxing during the playoffs when too many teammates haven’t shown up too often.

Nobody else on the Heat is doing much rebounding, so the small forward had to grab 18 in Game 1. That can take its toll.

“It is tough,’’ James admitted Friday before Miami practiced in preparation for Sunday’s Game 2 at AmericanAirlines Arena. “But it is what it is. I put myself in a position to try to do everything for this team, a little bit of everything, and put myself in a position to win. It’s very challenging mentally, physically. But you have to figure out a way to just have will at this point of the season. There’s not too many days left. There’s no room for excuses.’’

What’s going on here? One day James asks for a rest in the fourth quarter and the next day he admits it can be difficult performing so many tasks? Is he suddenly going human on us?

His teammates don’t seem to worry about that happening.

“He’s the best athlete in the world. Nobody’s tired,’’ center Chris Bosh shrugged when asked if James was getting fatigued.

“It it takes him 40-plus minutes and grabbing 18 rebounds, that’s what it takes,’’ forward Udonis Haslem said of James, who logged 42 minutes. “We all have different roles on different nights, but his role is everything. … We depend on him to do everything. Unfortunately, if him having to get 18 rebounds did fatigue him, then hopefully we got two days to rest him up and get him back out there on Sunday.’’

Yes, two days off should helpful for James. But he still experienced fatigue Thursday after having two days off following Monday’s Game 7 East finals win over Indiana.

What’s going to happen starting Sunday when the teams play three games in five nights? If James has to continue to carry an even heavier load, that might not be good news for the Heat.

Guard Dwyane Wade hasn’t been himself this postseason due to an extremely painful bone bruise on his right knee. Bosh often has been lackluster while hanging out mostly on the perimeter. He’s averaged a ridiculous 4.4 rebounds over his past eight games, meaning somebody on the Heat (calling Mr. James) has to get some boards.

With 18 points and 10 assists, James had a triple-double in Game 1. Still, his point total, the lowest of these playoffs and nearly seven below his seasonal average, raised some eyebrows.

After all, the former NBA scoring champion with the Cavaliers had said after a Game 5 win over Indiana he went back to his “Cleveland days’’ of being more aggressive offensively when the Heat really needed a win. Seems James could have gone back to those Lake Erie nights in the fourth quarter of Game 1 when the Spurs were taking control of the game.