The outing, scheduled to launch in Hamburg, Germany, on May 14, has been canceled.

“Davey has had really bad headaches for the last year,” his bandmates said in a statement. “These headaches came almost everyday, more so when he was singing. … Davey finally saw a neurologist, and had an MRI scan done on his brain. The doctor put him on new medication while waiting for the test results. He felt better for a few days, but then became really sick with headaches and vomiting right before the start of the European tour.”

The MRI revealed the fist-sized tumor. Despite the non-cancerous tumor’s size, neurologists were able to remove it, and vonBohlen faces a good prognosis.

He is recovering at Milwaukee’s Froedert Hospital and is expected to be released soon, according to the band’s label, Jade Tree Records. Doctors predicted a recovery time of four to six weeks.

The Promise Ring intends to eventually reschedule the European tour, which was scheduled to run through June11.

Meanwhile, original support act Burning Airlines is proceeding with all but a few of the European dates, according to a spokesman for Flowerbooking.