LONDON — Amir Johnson will not play Thursday in the NBA London game against the Boston  Celtics at The 02 Arena. The 76ers backup center has been sidelined because of gastroenteritis since Wednesday.

Richaun Holmes will back up Joel Embiid at center.

Johnson, 30, has averaged 4.8 points, 4.8 rebounds, 1.5 assists and 15.6 minutes in 36 appearances. He has started eight games.