So Cavaliers coach David Blatt put him on the bench.
Blatt held the four-time MVP out of a 93-86 loss at Indiana for precautionary reasons. James had hurt his back while scoring a season-high 42 points in Thursday night's 110-99 win over Golden State.
"It was my decision," Blatt said. "That was on me."
James did not talk to reporters following the game.
He was replaced in the lineup by James Jones, who started his career with Indiana and had played with James in Miami. Jones wound up with six points on 2-of-6 shooting, finishing with no rebounds and one assist.
Since entering the league in 2003-04, James has been one of the league's most durable players. He missed only 64 games in the previous 11 seasons -- with some of those coming late in the season to help him rest for the playoffs.
But this has not been the same kind of season for the two-time NBA champion.
He has now missed 11 games, at least nine of them with a bad back. And unlike previous times when James sat out, he didn't even sit on the bench with his teammates.
The timing couldn't have been worse for the Cavaliers (37-23), who have played their best basketball of the season over the past five weeks but have now lost twice during that span at Indiana.
For the rare sellout crowd at Bankers Life Fieldhouse, the move came as a surprise.
Some fans showed up wearing James' jersey and there was a significant enough portion rooting for the Cavs that they could be heard early in the game. Blatt didn't let anyone outside the locker room in on his secret plan until 90 minutes before tip-off.
"I wasn't very surprised that he didn't play," Kevin Love said of James' absence. "It was a tough back-to-back. A lot of things functioned into it. But we're not going to hang our heads. We're going to continue to get better."
James wasn't the only All-Star missing from Cleveland's lineup.
Guard Kyrie Irving stayed home to have an MRI on the left shoulder he also hurt in Thursday's victory. Matthew Dellavedova replaced Irving in the starting lineup and wound up with 14 points, 10 rebounds and five assists.
"Hopefully we'll have him back soon," Blatt said when asked about Irving's condition. "We just have to see how he responds to the treatment, but it's not too serious so that's good."
Blatt is hopeful James and Irving will both play Sunday in Houston.
James came into the game No. 3 in the league in scoring (26.0 points) and ninth in the league in assists (7.3). Irving also was ranked among the league leaders in scoring (21.7), assists (5.2), 3-point percentage (40.4) and free-throw percentage (85.7).
"We missed them," Dellavedova said. "But it was experience for everyone and I think we'll be better for it."