American Gay won the 100 metres, 200 metres and 4x100 metres relay at the world championships in Osaka, Japan which finished last week.
"Tyson is taking a break as he recovers from the world championships and will not run in Brussels," Barbara Huebner told Reuters in a telephone interview from Boston.
"But he is planning to
The Shanghai meeting is scheduled for Sept. 28 with Yokohama on Sept. 30 and Daegu on Oct. 3.
Gay has competed only in a 4x100 metres relay at Zurich since his gruelling world championships schedule.
"He just needs a break," Huebner said.
Gay's withdrawal from the Brussels meeting ended hopes of a showdown with Jamaican Asafa Powell, who on Sunday lowered his own 100 metres world record to 9.74 seconds.