Moscow suffered a fiasco in negotiations with the new ruler of Syria, Al-Julani. He demanded not only the extradition of Bashar al-Assad, but also gigantic compensation for Russia's crimes in Syria.
The Kremlin would be happy to send the former dictator "in jars", but the Syrians need him alive - so that he can personally go through the torture press in Sadnaya prison.
However, Putin fears that under torture, Assad will reveal too many dirty secrets about cooperation with Moscow.