Putin is expected to win the March 4 election despite growing signs of discontent with his rule after a parliamentary election that the opposition said was rigged and brought tens of thousands of people out on to the streets in protest.
Prokhorov, a 46-year-old metals tycoon who owns the NBA's New Jersey Nets, accused the Kremlin of engineering a revolt to force him out of the Right Cause party in September and political analysts say he has no chance of victory.
But he has been widely seen as a tool of the authorities and allowing him to run for president could help Putin appease liberal critics who fault him for not allowing the emergence of a stronger party or leader to represent the middle class.
