It's worth recalling, given the present situation, how Putin became president. In August 1999, [Boris] Yeltsin appointed him prime minister. In December, Yeltsin suddenly resigned. Under Russia's constitution, the prime minister succeeds the president in such circumstances, so Putin rose to become acting president giving him the presumptive lead in the election the following March.That sounds tailor made for a Russian spinoff of 24. But I suppose stranger things have happened.
Putin inherited the supreme presidential powers of Yeltsin's constitution. If Putin does run for parliament and then becomes prime minister, he might, as some speculate, pull the strings from behind the scenes, like a puppeteer, while the president who will no doubt be handpicked by Putin, just as Putin was handpicked by Yeltsin only pretends to make the decisions.
That's one scenario. There's another one, though, which would reprise his earlier path to the top: His handpicked president resigns soon after the election, and, to the cheers of hundreds of thousands who throng Red Square as witnesses, Czar Vladimir once more ascends to the throne.