David Cook visits cancer-stricken brother, performs on 'Idol' tonight
But he's appearing tonight on "Idol" in a taped performance.
The singer did not elaborate about why he took time off on his website, but Cook's brother Adam has been battling brain cancer.
He plans to get back to his tour Thursday. Concert dates are scheduled through October.
"David would like everyone to rest assured that we are working with the universities to reschedule the shows that are missed," says his website.
Fans have posted hundreds of messages of support on David's website.
Feel free to also leave your message of concern, prayers, hope and support here.
More David Cook dish: