James and Bosh, Miami's two big free-agent signings of the summer, played only the first quarter Saturday night as the Heat lost 90-73 to the San Antonio Spurs in a preseason game.
James scored 12 points and Bosh had two before spending the rest of the game on the bench in sweatsuits. The third leg of Miami's Big Three, Dwyane Wade, sat out his second straight game with a sore right hamstring.
One night after playing Oklahoma City, James said he could have played more "but I'll go off what coach [Erik Spoelstra] and the coaching staff want me to do and we go from there."
Spoelstra said he wanted to look at other players. But with Wade out, and James and Bosh getting limited minutes, it may take some time for the Heat to find their peak form.
"Tonight we took a step backward, but we had a lot of key guys out," James said. "We haven't put in a lot of our stuff, they haven't put in a lot of their stuff, so you just go and take it for what it is."
James, who signed with the Heat over the summer after seven seasons in Cleveland, got a mix of cheers and boos from the sellout crowd before the game. One woman held up a "LeBron Marry Me?" sign.
Once the action started, James scored 12 of the Heat's 26 points in the first quarter. Bosh, who scored 23 the night before, had a rough start. Blair went over him for San Antonio's first basket and Bosh missed five of his six shots in the quarter.
"If Coach wanted to hold me out and get some rest, I'm all for it," Bosh said. "I'm just going to have to get my legs again and get used to the NBA schedule again."
The Spurs also sat their stars for long stretches. Ginobili played 10 minutes of the first quarter, but Duncan logged only seven minutes and didn't play after the period. When a relaxed Duncan leaned on the media table to stretch, he waved to two schoolgirls who called his name, bringing a squeal from the young fans.
Like everyone else, Ginobili seemed anxious to see what James, Bosh and Wade can do when they get on the court together for more than a few minutes.
"In a lot of teams, there are two All-Stars and really good players, so I want to see them with Dwyane, too. It's going to be interesting to see how they adjust to each other," Ginobili said. "It's going to be really important for other players to make shots because they're going to be open."
James Jones put Miami up 46-40 when he was fouled on a 3-pointer and made the free throw. Then Ginobili and Parker showed they've still got some magic when Ginobili fired a bullet pass to Parker, who finished the play with a reverse scoop layup to trim Miami's lead to four at halftime.
Duncan was on the floor with Parker and Ginobili to start the third, but coach Gregg Popovich pulled him for Antonio McDyess a split second before the whistle to start play. The Spurs opened things up with an 18-2 run capped by Curtis Jerrells' long jumper that made it 63-53.
The Spurs outscored Miami 20-10 in the fourth. Miami committed 19 turnovers.
"I thought the whole bench did a good job defensively," Popovich said. "They were impressive with not just their effort, but their recognition. That was nice to see."
Richard Jefferson and Jerrells each scored 11 for San Antonio. Jones added 12 points for Miami.
"I think we're at a pretty good point right now," Bosh said. "It's only three games in and everybody here hasn't really played together."