This absence has
prompted rumors and speculation across the Russian blogosphere. "Putin has died" is now trending across the Russian internet, but there is no credible information citing what, if anything, might be afflicting him.
This kind of speculation may be natural given the secretive and autocratic nature of Putin's leadership. "These are the kinds of things that happen when a governing system is so dependent on the image of and physical person of one man," Hannah Thoburn, a Eurasia analyst with the Foreign Policy Initiative, told Business Insider. "This is certainly not the first time that similar rumors have happened. They happened under Yeltsin as well (although he really was in very poor health)."
If Putin is incapacitated, the Kremlin may try to keep that information tightly under wraps until all factions within the government have agreed to a successor.
Constitutionally, "Medvedev would take over as acting president for 90 days," Nichols said. "It's how Putin himself became president in 1999."
"But no, there is no way the Kremlin would announce [Putin's death] until all the deals have been cut," Nichols added.
Here are the best theories about why Putin has disappeared - Yahoo Finance