Maybe my view of Russian politics is biased, but I cannot see a path to anyone other than Putin winning...
Alexei Navalny might, but he is not allowed to run. Some Russian law says a guy on a suspended sentence is not allowed to run, so they brought some politically-motivated charges against Navalny, (shock!) convicted him, suspended his sentence (to be magnanimous, so they said) and, boom, most popular viable opposition candidate is ineligible and the big guy wins.
At his recent Q&A, Ksenia Sobchak asked him why he would not let Navalny run. He said "We do not want Russia to become like Ukraine." Ukraine has had five competitive elections since independence and the incumbent has lost four of those elections. 'Nuff said.
The Russians used to have a box on the ballow marked "Против всех," (against all). That's how I feel in many US elections.