Or, and this is likely to be the preferred option, [Putin] will try to have his cake and eat it too: by saving face inside Russia and also avoiding further isolation abroad by “freezing” the conflict. In this scenario, Moscow would call for immediate cessation of hostilities, a ceasefire, and an international “peace conference” that would include the EU, US, Russia, the “self-defense forces” and Ukraine. In the meantime – and it could be a very, very long time – the rebels will remain in control of the territories they hold today.
(Leon Aron at AE Ideas)
Putin is just brazen enough to attempt to play the peacemaker and honest broker over Ukraine. Even at this late stage, I bet he thinks he can switch from being arsonist to fire chief. After all, it worked for him last year when he successfully stepped in to protect his ally Assad from paying the price for gassing civilians. I can well imagine him thinking it's worth trying the same trick again to save his own bacon.
On the other hand, I can equally imagine Putin going for another option Leon Aron mentions:
After new sanctions are imposed, Putin may very well decide that having paid the price he might as well double down by sending regular troops to save his proxies and help them hold Luhansk and Donetsk.As Aron says, "Stay tuned!"