Illinois basketball will officially open its 2026-27 campaign on Monday night against Fairleigh Dickinson (7 p.m. CT, Big Ten) without its preseason All-American David Mirkovic.

Mirkovic, who has been recovering from foot surgery back in early August, appeared poised to miss the game regardless. But after Sunday's news, we're learning that it just his foot that will be holding him out from the season opener.

David Mirkovic undergoes an appendectomy before 2026-27 season

“Obviously, Mirk is going to be out,” coach Brad Underwood said Sunday in his pregame press conference. “And then he’s had a continued setback, as he had appendicitis – appendix removed last night.

“And so, we don’t know what that means. I can’t give you any further update than that. So, was in an emergency room, having his appendix removed last night. So, obviously that means he won’t be in uniform.”

According to the Cleveland Clinic, a full recovery from an appendectomy takes about six weeks. Obviously, everyone is different. Mirkovic, though, will have top-shelf resources at his disposal throughout his recovery. And, presumably, Mirkovic may also need additional time to ramp up his conditioning (which could extend the timetable for his return to the court).

A six-week timeline would have Mirkovic targeting a return by approximately mid-December. Again, though, without much detail from Underwood, it’s impossible to know Mirkovic’s exact outlook.

It seems improbable that Mirkovic would return by Nov. 10 for the trip to Texas Tech. The following week – Nov. 17 – at Duke also seems highly unlikely. And a return for the UConn clash in Chicago on Dec. 4 may be optimistic (though possible).

What does David Mirkovic’s extended absence mean for Illinois?

Most obviously, it means that the Illini frontcourt depth is going to be tested. Tomislav and Zvonimir Ivisic should be capable of shouldering a heavy load – but now circumstances demand it. Additionally, Underwood could elect to play small, which might push Andrej Stojakovic to the 4. (Both Zvonimir Ivisic and Stojakovic are expected to play vs. FDU, per Underwood.)

Either way, though, Jason Jakstys is going to have his number called. Underwood has raved about Jakstys, and we’ll see firsthand if Jakstys is actually ready for the moment. Freshman Landon Davis may also need to give Illinois legitimate minutes.

The Illini will survive their non-conference slate – and maybe be even stronger for working through Mirkovic's absence. But those three high-profile non-Big Ten outings are going to be that much more challenging without him.

The result of each of those – Texas Tech, Duke and UConn – may be the difference between Illinois earning a No. 1 seed in the NCAA Tournament and a No. 2 or 3 (or worse). If the Illini drop all three – which is entirely possible, if not probable, without Mirkovic – then a No. 1 seed in the Big Dance may be quite difficult to come by, even with an impressive Big Ten season.