James has been bothered by a cold all week. Already without Dwyane Wade because of an ankle injury, the Heat wanted to give James some extra time to rest so they sent him home early Thursday morning.
The Heat, who are 4-0 this season without Wade, also activated center Eddy Curry for the first time this season. Curry hasn't played in a game in two seasons. He checked in with 2:20 left in the first quarter.
Curry had not played since Dec. 17, 2009, for New York against Chicago. He started his career with the Bulls, then played in parts of five seasons with the Knicks. Thursday's appearance was Curry's 11th since the start of the 2008-09 season.
Heat coach Erik Spoelstra said earlier Thursday that James would be a game-time decision.
"He didn't feel good last night," Spolestra said. "That bug has been going around."
James was one of several Heat players who got sick following Miami's five-game road trip, which ended last week. He battled through it during Tuesday's victory over the San Antonio Spurs, scoring 33 points, though he started the game 1-of-7 shooting before settling in. James was able to practice with the team Wednesday.
James Jones started in Wade's place.
Mike Miller, who went 6-of-6 on 3-pointers in his first game of the season Tuesday, played after spraining his ankle in the game.
Meanwhile, the Lakers -- and James' former coach -- fully expected him to play.
"When you talk about great players like him, those guys, even though they're sick or a little injured or whatever, they find a way to perform at a high level," Lakers coach Mike Brown, one of James' former coaches with the Cleveland Cavaliers, said Thursday afternoon. "I don't think it's any different for LeBron."
With James is in the lineup, the game featured the NBA's top two scorers this season -- Kobe Bryant at 30.8 points per game and James at 29.8.
Head-to-head, James and Bryant have remarkably similar numbers. In the past 11 meetings, James is averaging 27.9 points, 7.6 rebounds and 7 assists, while Bryant is putting up 28.0 points, 5.9 rebounds and 5.6 assists.
There is one significant difference in that span: James' teams have gone 9-2 against the Lakers.
Brian Windhorst covers the Heat for ESPN.com. Information from The Associated Press was included in this report.