If you are reassigned, you are not dead weight to your original division, because you aren't working for them, you are on the books of the other division.
Also if you are reassigned, you don't have your original projects to get behind on, they are someone else's problem now.
Similarly, if reassigned, and you do the work of the new assignment there's no grounds for a PIP, and even if there were, your original manager wouldn't be the one putting you on it.
Still bad, but probably means that all this was inevitable, and his manager already made up their mind before the project even started.