Dwyane Wade, however, continues to prove he's still just as important.
With James ailing, the Heat may need another big performance from Wade as they go for a fourth straight win Saturday night against the visiting Boston Celtics.
James is working his way back to fitness from nagging lower back soreness that's troubled him so far this season. Despite the injury, the four-time MVP is averaging 24.3 points, 7.7 assists and 5.5 rebounds while hitting 56.4 percent of his field goals.
The back slowed his production Thursday, scoring 18 points with six assists and five boards in a 102-97 win over the Los Angeles Clippers to open this four-game homestand.
"I would probably have to not be able to get out of the bed," James said when asked what it would take for him to miss a game. "Can't get out of the bed, then can't show up here.
"I've had a history of it, but I always keep a good eye on it so I should be all right. It ain't a great feeling, I'll tell you that -- especially at nighttime when you're trying to sleep."
While James' status may depend on his ability to climb out of bed, Wade could provide the difference again after he had season highs of 29 points, seven assists and three steals against the Clippers.
"Everyone said he was done," coach Erik Spoelstra said. "Go figure."
Wade has scored at least 20 points in four straight games, and Miami (4-2) has won 51 of its last 57 games when he's reached that mark, including the playoffs.
"I know I can play basketball," Wade said. "I know when I'm healthy what I can do."
The Celtics are surely aware of that, too. Including playoffs, Wade averages 25.4 points over the past 11 home meetings, while James is scoring 32.3 with 10.3 rebounds in the past 12 overall.
The Heat have won 10 of past 12 home matchups, including four of five in the regular season.
Boston (2-4) seeks a third consecutive win after opening the season with four straight defeats. The Celtics followed a 97-87 victory over Utah on Wednesday with Friday's 91-89 win at Orlando.
"We talked before about making winning plays in winning time, and we did. That was neat," first-year coach Brad Stevens said Friday. "Overall, I'm very pleased with the result but we still have a lot to work on. We're not that much different than if we wouldn't have won the game."
Brandon Bass has been a big part of the recent success, totaling 36 points and 11 rebounds in two games after making 5 of 19 from the floor to score 12 points over the previous two.
The forward had a team-high 16 points and grabbed seven boards against the Magic, while Jeff Green struggled to score 10 on 5 of 14 from the floor.
Green has 68 points on 24 of 38 from the field with 15 rebounds in his last two games against the Heat, including a career-high 43 in a 105-103 loss March 18.
Jeff Green made a game-winning three point field goal at the buzzer Saturday against the Heat, his seventh game-tying or go-ahead shot in the final 5 seconds in his career.
Since entering the league in the 2007-08 season, Green has the highest field goal percentage in the NBA on game-tying or go-ahead field goal attempts in the final five seconds of games, minimum 10 FGA.