This rumor sounds absurd. What is not absurd, though is the notion of firing Pioli mid-season. There are valid reasons to do it right away if the plans are to do it anyway.
- Send a message to the fan base that change is coming swiftly.
- If reports of Pioli being a meddling cancer are true, then it removes the cancer.
- Maximize time allowed to find a new GM.
- If it's possible to hire new GM prior to season end, it would allow them more time to evaluate coaches and get scouting org together.
If the plan is to fire Pioli anyway I can't think of any reason to NOT do it right away.