Pagano has acute myeloid leukemia, where the bone marrow is producing abnormal white blood cells that interfere with healthy blood cells. Symptoms can include weakness, weight loss and easy bruising or bleeding. Treatments can include chemotherapy, drugs and radiation therapy.
"He is ready to take this fight on and he is a fighter," Irsay said.
Pagano waited until the Colts' bye week last week to be checked out after experiencing extreme fatigue and bruising, starting in training camp.
Pagano believed he was experiencing football fatigue, but a blood test early last week revealed the diagnosis of leukemia.
Pagano has been in lockdown since last Wednesday in an intensive care unit of an Indianapolis-area hospital, where he has been receiving treatment.
Dr. Larry D. Cripe said at the news conference that Pagano is undergoing chemotherapy treatments and had done well so far. The goal of the treatment is to "cure" Pagano, which means the disease remains in remission for 3 to 5 years.
Offensive coordinator Bruce Arians will serve as the interim coach in Pagano's absence. Irsay said that Pagano requested that Arians coach the team while he is undergoing treatment.
Sources said Pagano will be out a minimum of six weeks, but that he plans to return as coach.
He confirmed in a text that he plans to return, writing, "Will be back soon."
Irsay, however, said it was unlikely Pagano would be able to assume full-time coaching duties this year.
"It is unlikely he will be all-in as a head coach this season," Irsay said.
Irsay also addressed Pagano's situation in a tweet Monday morning, asking NFL fans to keep the coach in their thoughts.
