Messi is the only player to win the prize, which recognises the best player in the world over a calendar year, since it became an official FIFA award back in 2010.
Ronaldo has finished second in two of those votes but, while Messi's 2013-14 campaign has been marred by injury, the Portugal international has been in superb form.
The 28-year-old attacker has scored 24 goals in all competitions for Real so far this term, and Ramos feels the former Manchester United man is now a level above his Argentine counterpart.
He told Movistar: "In previous years maybe not, but this year it is being demonstrated that, although he has always been seen as the best in the world, Messi is now a notch below Ronaldo.
"The Ballon d'Or has to be given to the best player of the moment."
The 23-man shortlist for the Ballon d'Or will be narrowed down to the three in December, with the winner announced on January 13 2014.
‘The pure simplicity of the way Slot has managed the squad is probably the biggest thing I could say about him. It’s not broken, so let’s get on with it’: Liverpool legend full of admiration for Jurgen Klopp's successor at Anfield
‘I trained at Spurs and thought they’d give me a chance. But I received a letter thanking me but saying they didn’t think I was good enough – I was gutted’: How Tottenham missed out on signing Wales legend John Toshack
