DeGraw says he plans to be back performing by Aug. 24.
According to a statement sent out by his representative Thursday, doctors have advised the singer to take more time to heal after being beaten up Sunday by an unknown group of men in New York City.
He was hospitalized with a concussion, broken nose, facial cuts and other injuries.
An investigation is ongoing and no arrests have been made.
DeGraw posted an update to fans on his Twitter page Tuesday afternoon, saying he didn't remember much and thanking them for their concern. "Hi my friends. Honestly, I don't remember much. I only know I can recover from here. Thank u all for your genuine concern. I love u guys," he tweeted.
The 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.