The point is that introducing troops won't suppress the protests – if he doesn't understand that, then he's a complete idiot. But it's hard to believe that.
If troops are introduced, Putin will immediately abandon him, as he has gained weight in the world as a "peacemaker" and will not support Yanukovych.
It is also worth paying attention to how everything is presented in Russia and in foreign media. It should be said that they are observing what is happening quite restrainedly.
In my opinion, this indicates that Russia has taken a position of observer, not a supporter of Yanukovych, and if Yanukovych understands this, he will not introduce any troops.