Former Netherlands midfielder Edgar Davids has claimed that Real Madrid's Cristiano Ronaldo "is just an athlete", while Barcelona forward Lionel Messi is "an anomaly".
Ronaldo and Messi, along with Neymar, have been named on the three-man shortlist for the latest Ballon d'Or award, with the winner to be announced in January.
Davids, who has tipped Messi to win it, has also said that replicating Ronaldo is more of an achievable goal than trying to become Messi.
"Messi is just an anomaly: he can dribble, he can score, he can pass, he has the vision, he understands the game. Ronaldo is just an athlete. He works so hard and back to back, he is always there," Davids told FIFA's official website.
"But if you work hard, can you be like Messi? No, that's impossible. Can you be like Ronaldo? Yes, to a certain extent."
Messi has won the Ballon d'Or on four occasions, while Ronaldo has won it three times, including in each of the last two years.