James had been sidelined since Nov. 2 due to an abdominal strain. He finished with 23 points in 32 minutes and added six rebounds and two assists as the Lakers lost 130-108 to Boston.
L.A. lost 109-102 to the Milwaukee Bucks on Wednesday to fall to 4-6 without James this season but were 4-2 with him, despite James not playing up to his usual standards.
In those six games, James averaged 24.8 points -- his lowest scoring output since averaging 20.9 points as a rookie -- while also averaging his least amount of rebounds (5.5) since his rookie year and his least amount of assists (7.0) since 2015-16. His 46.7% shooting mark from the field is also his lowest since shooting 41.7% as a rookie, and his 4.2 turnovers per game are tied with his 2017-18 season for his career high.
In 54 career regular-season games in Boston, James came in averaging 28.9 points per game, his highest scoring average in any road arena other than Cleveland, where he has averaged 29.1 points in 17 games as a visitor.