Barcelona star forward Lionel Messi claimed that he is unsure of his friendship with leading footballer Cristiano Ronaldo in the coming years.The Argentine and Portuguese international share nine Ballon d'Or awards amongst themselves."I don't know if we will be. Friendship is built through spending time together and getting to know each other," the 30-year-old was quoted saying by Spanish website Marca on Saturday. "We have no relationship, mainly because we only see each other at awards ceremonies and that's the only time we speak. Everything is fine, but our lives don't cross over very often," Messi added. The four-time European Golden Shoe holder also said promising youngsters Neymar, Kylian Mbappe and experienced striker Luis Suarez have the potential to win the Ballon d'Or in the coming years. "There are many great players around today who can win the Ballon d'Or. In recent years there have just been two, but now players like Neymar, Kylian Mbappe and Luis Suarez can compete for that award," Messi said.