I think the whole point of releasing the memo is to put the pressure on Rosenstein. He’s the only one who signed a FISA warrant who is still a federal employee (not counting McCabe who semi-resigned the other day). They are showing Rosenstein they have the goods on him and could remove him for cause, and the implication is that the only way for him to avoid that is to order Mueller to wrap up the probe.
Even if he fires Mueller or dissolves the Mueller probe, he should still be relieved of his duties.