Brett Dawson of The Athletic previously reported the forward didn't practice Saturday because of a thoracic muscle strain and was considered doubtful for Sunday's game.
While the timeline for a return is not yet known, any injury news is a concern considering what the Lakers went through last year.
James went through a disappointing 2018-19 season where he played a career-low 55 games. A groin injury kept him out for more than a month in the middle of the year, and he spent more time on the bench because of load management at the end of the season.
This came after playing all 82 games for the first time in his career in 2017-18.
The injury effectively killed last season for the Lakers, and another extended absence could have a similar negative effect for the current squad.
Anthony Davis can certainly carry the team on his own, but Los Angeles will need a lot of help from its depth to help overcome the loss of James.
The 34-year-old has remained an elite player, averaging 25.8 points, 7.5 rebounds and a league-best 10.6 assists per game so far this season. This has continued a trend of the forward filling up the stat sheet in a variety of ways even more than earlier in his career.
If he can stay healthy, the Lakers can contend for a championship and at least make the playoffs for the first time since 2013. However, a serious issue could create another setback for Los Angeles.