SAN ANTONIO — Game 4 of the NBA Finals will tell more about the Miami Heat than a 66-win regular season ever could.

Any questions about LeBron James and the Heat were supposed to have been answered by now. He was too good to be taken out of games, his teammates too talented to go through long stretches where they weren't contributing.

But they didn't resemble the league's reigning powerhouse in Game 3, when the San Antonio Spurs handed them the third-worst beating in finals history in a 113-77 romp. They looked like the confused club from two years ago, when the finals last came to Texas.

Another loss tonight and they're on the verge of something much bigger than another finals failure.

Lose this series, and the whole Big Three era might be a failure.

"Something has to give tomorrow," James said Wednesday. "They have a championship pedigree. They have four (titles). We have two. So something has to give. We'll see what happens. We've been able to bounce back throughout adverse times throughout the season throughout the years that we've been together, these three years. We'll see."

"We'll see" is the approach the Spurs are taking with Tony Parker, who has a mild hamstring strain. The team is calling the All-Star point guard day to day after he was hurt during Game 3 and had an MRI exam Wednesday.

"I want to wait until tomorrow before I make a decision whether he should play or not," Spurs coach Gregg Popovich said. "And obviously a lot of it will have to do with Tony, and what happens to him during the day, and how I think his play will affect our team, whether good or bad."

The Spurs didn't need much from him Tuesday, when Danny Green and Gary Neal combined for 13 of the Spurs' NBA Finals-record 16 3-pointers and Kawhi Leonard had 14 points and 12 rebounds, essentially playing James even.

James had his practice jersey hanging over his back like a cape Wednesday, and he knows the Heat need him to be Super on Thursday.

And he insists that what he's going to be.

"As dark as it was last night, can't get no darker than that, especially for me," he said. "So, I guarantee I'll be better tomorrow for sure."

He should, given that his 7-for-21 effort with no free throws was about as bad as the four-time MVP can play. But he came to Miami so he didn't have to do it all, where a partnership with Dwyane Wade and Chris Bosh meant his days of having to carry teams were supposed to be over.

But with Wade battling right knee pain for a while and Bosh mired in a slump, there has rarely been the vaunted three-man attack that was expected when they joined up in July 2010.

"If us three don't lead the charge, we're not going to be NBA champions," Wade said. "Our teammates count on us, so we have to step up."

Some of the problem could be fatigue for a team that was forced into some playoff-atmosphere games in the regular season while trying to extend what became a 27-game winning streak, the second-longest in league history. With a huge lead in the standings in March, the Heat could have instead opted to give their veterans some extra rest.

That's what Popovich has always done, essentially sacrificing a couple of lengthy winning streaks in recent years by resting key players when they were still intact.

"There are no right and wrong answers to the way people do things, because it's pretty hard to assess and evaluate," Popovich said. "Suffice to say, everybody has a different approach to playing time or when to sit or not sit players. And we do it one way, other teams do it differently. There's no one to say one way is right or the other way is right."

But the Heat's way will be second-guessed — just like everything about them is — if they don't pull out this series. There will be calls to break up the Big Three, criticisms of James, and everything else that Tim Duncan and the Spurs never had to deal with in small-market San Antonio.

"I guess if you allow yourself to be affected by it and you allow yourself to look and read everything, then everyone is under a microscope," Duncan said. "As I've said, I don't envy that kind of scrutiny and pressure in any way."

It's what the Heat signed up when James arrived and guaranteed titles three summers ago, and the pressure became even greater after they flopped the first time with their loss to Dallas at the end of their first season together.

The Heat looked so vulnerable then, but seeing them as bewildered as they were Wednesday was stunning. James too often seemed to linger around the perimeter, an old habit reappearing when it seemed he'd put it aside for good and wouldn't allow himself to settle for jumpers anymore when he could go into the post instead.

Part of the reason is the Spurs, with a solid defensive game plan and a versatile defender in Leonard who can apply it. But the Heat also realized another problem was simply their own effort — or lack thereof — in going for rebounds and loose balls.

"We just collectively played a very bad basketball game last night,"  Heat coach Erik Spoelstra said. "And that was everybody, including the staff. It was hard to really judge anything and evaluate anything from that game.

"That's why after the film session, all we're focused on is how we prepare the next 24 hours to have our best game of the series tomorrow night."

Game 4 is where the Heat started to lose control of the series against Dallas two years ago, but they know it's where they have to regain it this time. They haven't lost two in a row in five months, and this isn't the time for that to end.

"We've been at our best when I guess our backs are up against the wall, and we're at it again," James said. "We'll see how we respond tomorrow."