He originally checked out with one minute left in the third quarter—his first time out all game—and went straight to the locker room. He returned to the bench but remained on the sidelines for a few more minutes, as captured by Sports Illustrated:
He eventually checked back in a few minutes into the fourth quarter.
James gave the Cavaliers a scare early in the preseason when he injured his ankle on Sept. 28. It didn't carry into the regular season as he's appeared in every game to this point.
Injuries have never been a significant problem for James. He did miss 13 games during the 2014-15 season due in part to back issues, but that's the only season in which he's missed more than eight games in his career.
Through the ups and downs for Cleveland, James has done everything in his power to carry the team. The four-time NBA MVP is having one of his best seasons with 27.5 points, 9.1 assists and 8.6 rebounds per game.
With James on the sidelines for the time being, the Cavaliers can use Kevin Love, Larry Nance, George Hill, Tristan Thompson, Jeff Green and Kyle Korver as the main lineup.