Indianapolis Colts head coach Chuck Pagano has been diagnosed with leukemia, and just several weeks into his first tenure as an NFL head coach, he’ll now be taking a leave of absence.

That absence, of course, is a far lesser concern than his health. Mike Freeman of CBS Sports reports that Pagano is expected to miss up to a month, while ESPN’s Chris Mortensen says that offensive coordinator Bruce Arians will take over as the interim head coach.

Thankfully, Pagano’s leukemia is considered “very treatable” according to ESPN, which is the reason for the anticipated short absence. The Colts have scheduled a press conference for 10:30 a.m. CT.

Pagano had experienced unusual fatigue in recent weeks, and decided to have his blood tested during the Colts’ Week 4 bye. The results then showed the need for treatment.

A top Colts official said that the team is “very optimistic” about Pagano’s recovery, and in a text to NFL Network’s Albert Breer the coach himself said he’ll “be back REAL soon.”

Colts owner Jim Irsay asked fans to pray for Pagano, saying he’ll win his battle.