Kirilloff was removed from his rehab assignment with Triple-A St. Paul on Saturday due to a flareup of soreness in his back, Do-Hyoung Park of MLB.com reports.
Kirilloff started up the rehab assignment Friday but lasted just one game before succumbing to another setback. The 26-year-old was placed on the injured list in June due to a back strain and nerve-related issues, and he was also briefly slowed by an ankle sprain earlier this month before starting up the rehab assignment. Even if Kirilloff's setback proves to be just a minor concern, he shouldn't be expected to return from the 60-day injured list until at least September.