The continuing US policy of regime change in Syria leaves little possibility that the [Syrian] government can recover Syria east and north of the Euphrates River. That land is under US government "protection." How the movement of (US) Kurds to Afrin to fight will affect that is unpredictable.
As SST forecast just after the fall of Aleppo City to the government, Idlib Province has become a cancerous wound in the side of the possibility of a fully reunited Syria.
The Turks are taking advantage of their burgeoning relationship with Russia to eradicate Kurdish control of Afrin district in Aleppo Province. The Turks are making steady progress in this effort.
The evolving tie to Russia is evident in the S-400 SAM deal and Russia seems complicit in the "Olive Branch" campaign. There are clearly limits to Russian protection of the SAG [Syrian Arab government]. The Turks have now established "observation posts" of company size all along the eastern border of Idlib Province. These are positioned to impede a renewed advance of R+6 into Idlib Province once SAA and friends are finished in the Damascus area.
The latest of these posts is now being placed just NW of Aleppo so as to prevent an advance by the government to the west into northern Aleppo Province. IMO what we are seeing is a slow motion annexation of NW Syria by Turkey.