Indianapolis Colts owner Jim Irsay has been placed on Injured Reserve with a gnarly illness … forcing him to back out of an upcoming concert with his band.

The news just came out Tuesday morning … with Adam Schefter releasing a statement from the Colts on 64-year-old Irsay’s condition.

“Jim Irsay is currently being treated for a severe respiratory illness,” the team said.

Irsay was slated to hit the stage alongside his “Jim Irsay Band” rock group as part of an exhibit and concert event in Los Angeles on Thursday … which will feature items from his massive music and sports memorabilia collection.

The band — which is slated to have special appearances from Kevin Cronin of REO Speedwagon, Billy Gibbons of ZZ Top and more — will seemingly hit the stage without Irsay, who served as main vocalist for previous gigs.

“While this unfortunately means he won’t be able to perform with his band this week in Los Angeles, he is receiving excellent care and looks forward to returning to the stage as soon as possible,” the team added.

“We’ll have no additional information at this time and we ask that you respect the privacy of Jim and his family as he recovers.”