It looks like Erdogan has been offered an easy option by Putin.
The options narrowed to these
1) Go full on invading Syria Mr.Erdogan.
We will bring the full force of our airforce and our air defences to bare, we will transport s-400 Triumf
to Aleppo and lock-on to Turkish targets.
2) Give the appearance of reasonableness, co-operate with Russia and Syria and we will let you save some face in Public.
3) Withdraw your forces before we destroy them.