DeGraw is still recovering from an attack on the streets of New York this past weekend.
A group of men randomly beat him into a concussion, even breaking his nose.
DeGraw was set to open for Train on Sunday at Musikfest.
But doctors told him he needs more rest.
Police are still investigating and DeGraw has said he doesn't remember much about it.
Other cancelations include dates in Nashville, Chicago and Toronto. However, he will resume his tour with Train and Maroon 5 on Aug. 24 in Columbia, Md.
The 34-year-old singer-songwriter's hits include "Chariot" and "I Don't Want to Be."
The Associated Press contributed to this report.