Kansas City placed Thompson (undisclosed) on the active/non-football injury list Tuesday, Aaron Wilson of KPRC 2 Houston reports.
Thompson being placed on the NFI list to begin training camp isn't surprising, as he suffered a seizure and cardiac arrest during a team meeting back in June. Kansas City will doubtless take every precaution with Thompson's recovery as he works his way back onto the practice field. He'll be eligible to return from the NFI list at any point during training camp or the preseason, once cleared to practice.