1400's?
Miracles are needed, like......Timur living longer and a much much much more thorough breaking of the Ottoman sultanate. Just send the Turks into a disarray in Anatolia and extend some sort of control over them.
Even if that manages to destroy most of the Ottomans, it still leaves European enemies. The one good thing about those of the Europeans that were Orthodox was that they'd most likely claim the empire and have some sort of legitimacy recognized by their contemporaries. The catholics would probably fuck up the system much more than the slavs and bulgars would in the event of Rhoman conquest.
If they manage to take advantage of the falling Ottomans and the amount of sheer chaos that would bring they could drag themselves kicking and screaming into surviving awhile longer in the form it had been for some time.
The Empire was surrounded on all sides, someone was bound to take a crack at them.
But to actually answer the OP, not possible. The Ottomans either win or die by another's hand. Rome doesn't have that sort of strength to put the Turks in their place under the Osmans.