Deng remained in Chicago after sitting out Thursday's Game 6 against the Nets and did not accompany the team to New York for Game 7.
The Chicago Tribune said Deng developed complications after undergoing a spinal tap this week.
Deng averaged 13.8 points, 7.6 rebounds and 3.8 assists in the first five games of the Eastern Conference quarterfinals series against the Nets.
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