Idiom for promoting someone to get rid of them

Question

I feel certain that there is a common phrase for this, but for the life of me, I cannot remember it:

What idiom is there for the concept of promoting someone as a way of keeping them out of the way? Someone you don’t want to fire or lay off, possibly because of their long service and wanting to reward them, possibly because of concerns about the PR or morale effect of such a lay-off, whatever, but someone you don’t want to have to deal with. So you promote them into a position where they cannot advance and cannot influence matters important to you, and they’re just stuck there.

The position they end up in is a “dead-end job” but it’s far from the only, or most common, form of dead-end job, so that phrase doesn’t help me. I am looking either for a phrase describing the act of promoting someone in this fashion, or a phrase describing this position very specifically, so either

He was [promoted] to chief pencil-pusher.

or

His was promoted, to chief pencil-pusher, a [dead-end job].

With “[promoted]” or “[dead-end job]” replaced with a more specific idiom that refers to this particular situation.

Answer 1

"Kick Upstairs"

to promote to a nominally higher level so as to be rid of on a lower, but more effective, level, as in a corporation

Answer 2

Perhaps the Dilbert principle (from Wikipedia):

The Dilbert principle is a concept in management developed by Scott Adams, creator of the comic strip Dilbert, which states that companies tend to systematically promote incompetent employees to management to get them out of the workflow.