Dwane had been feeling unwell for several days, and then Monday went in for emergency surgery to relieve the clot found on the surface of his brain.
"Ted is receiving excellent care and we are being assured he will recover quickly from surgery," the statement said.
In light of Dwane's ailment, Mumford & Sons canceled three shows, in Dallas Tuesday, Woodlands, Texas Wednesday, and New Orleans Thursday.
The band said the three shows will be rescheduled, and has no plans to cancel any additional performances.
Notable deaths of 2014 [PHOTOS]